A guide to expanding against independents in multiplayer, and how to prepare for that.
To Flow Outwards Like An Ideal Liquid
At the start of a typical game of dominions you control only one province - your capital.
Expansion, expanding, 'earlygame' are all words used to describe the process of taking provinces from the grey-flagged independents ('indies'). In singleplayer this can be quite a leisurely experience - in multiplayer it is a harshly competitive race to see who can expand fastest to gobble up land. If you already own land, most players won't contest it unless it is in their 'cap circle' - provinces directly adjacent to their capital. While more experienced players will contest land taken too far away from someone's capital, or that is too 'greedy', in mixed games they might refrain - as less experienced players often respond to that not with a shrug and an oh well, but rather with war to the death at all costs and early wars that drag on ('hell wars') can cost someone the game.
Unlike many other facets of the game, you can practise expansion quite easily in singleplayer. A general rule of thumb is that on a blank map (a map with only 1 AI and a lot of provinces, so you are unlikely to see them during the expansion test), you should be able to expand to 20-25 provinces by turn 12. This should mean that in a competitive mp game, you can reliably get at least 15 provinces (as enemy players' expansions will cut you off in MP and they won't on a blank map).
Three To Tango, But Only Two To Dance
Most nations need at least one of the following expansion strategies to ensure a timely expansion and avoid being a pocket nation (the most common cause of defeat). However, if you desire a larger expansion than average, you can take more than one on the same nation (although often at the cost of good scales or powerful bless).
They can generally be defined as the following;
Prod and Order: Taking a high level of prod and order (or only one, for some nations) and recruiting national troops in large numbers to form expansion parties quickly enough. Mostly useful for nations with troops that work well vs independents, or that are especially spammable (low rec and res cost for reasonably effective troops). This strategy usually relies on clearing out the cap circle early on, to allow resources to flow to the capital and allow more troops to be built.
Awake Expander: An awake god, such as a Myrmecoleon, Great White Bull, Thrice-Horned Boar or other monster that can reliably take out independent armies. This scales from gods that can only take out weak independents up to ones that can casually faceroll most - very rarely however will gods be sent against heavy cavalry, horse tribe, or barbarians if it can be avoided, as losing an expensive expander can be catastrophic. Certain non-monsters, such as the Tiwaz of War and the Virtue, can expand also, albeit a bit more expensively, and often they want a suit of armour or a weapon to do so against tougher indie types.
Expansion Bless: Some nations will take a bless for sacred units and then use those sacreds to expand (as the bless makes them powerful enough to take on indies in small numbers), however there are also specifically expansion focused blesses (most blesses tend to be aimed at fighting elite enemies or mages, not masses of low quality troops that indies typically use), which are much cheaper for the same job. These often involve stacking +Attack on troops with long weapons to make them repel weak indie attacks, or adding barkskin or invulnerability to armoured sacreds to make them relatively invulnerable to weak indie weapons.
They Are Your Foes - Infidels, Unbelievers: Be Angry!
Understanding what types of independents ('indies') exist on the map and what strategies you might need to deal with them (or more commonly, what size of expansion party) is an important part of expanding. Scout reports (how many men the game tells you are in the province) can be inaccurate, incorrectly reporting the numbers of units in the province (iirc, to as low as 50% or as high as 150%). Ergo they are best treated as a rough guideline - seeing scout reports for multiple turns will give you a better idea of the actual numbers in the province.
In general the best understanding of what you can use to defeat what comes from practice. I can describe the units here and give some ideas as to what counters them or what is needed to defeat them but only through experience will you be able to finesse the best groups for killing them with minimal investment.
Barbarians: Angry men with great big hammers (and swords). Barbarians hit REALLY hard but have almost no defense. They don't parry well, and wear very light armour. Ergo they are uniquely vulnerable to archery, but gaining enough archers quick enough to take advantage of this in a reasonable amount of time during expansion is quite hard. This means you will often just use regular melee troops to fight barbarians. They are notably a lot easier for nations whose expander troops are using javelins (such as the Roman factions), as javelins will make a bloody mess of them as they close. Many an expander god has died horribly to barbarian mauls, and they are generally one of the poptypes to avoid with expander gods if you have a choice in the matter. Barbarians benefit from larger groups taking them on, routing them in a single turn so they don't have time to bring their horrible mauls to bear.
Deer, Wolf, Bear, Lion Tribe: While there are some differences here (wolf have double daggers, deer have spears etc) tribals are generally considered one of the easier poptypes. They wear light armour like barbarians, but are naturally more spread out so using archery against them is somewhat less effective - keeping in mind that typically massing enough archers during expansion is still too hard anyway. Most armoured guys will cut them up and anything tough or killy will tend to roll them.
Light Infantry, Archers, and Militias: Although they come in many combinations, these are generally considered the weakest indies in the game. Unlike tribals who can random into large numbers of melee guys and bumrush you with 40 hatchets or something, militias can't hit anything and light infantry are generally very few (being usually a quarter of the poptype at most). Of these guys, only light infantry are generally dangerous, having normalish combat stats, a spear, and sometimes a javelin.
Heavy Infantry (+/- archer, light infantry, militia): Generic human infantry that wear chainmail (or other era appropriate garb but never as heavy as plate), heavy infantry are largely dangerous because they can take light hits of damage and live. They are usually not much of a problem because the poptypes they come in include lots of other stuff - archers, light infantry etc, so you are rarely facing more than 15 total heavy infantry at any one time and usually less. If you're running knife-edge expansion groups of small numbers of national infantry though, they can bounce off heavy infantry (often by ending up wasting lots of attacks on shield hits against the heavies while some light infantry stab them).
Horse Tribe: An interesting poptype, horse tribe are entirely mounted, all archers, and have good melee stats (largely due to being mounted). While their lack of a lance means you can generally overwhelm them in melee, they are a tougher poptype and things vulnerable to arrows or that have trouble hitting stuff will have issues with them. One of the poptypes that people will often combine expansion groups poorly suited to dealing with them to deal with.
Light Cavalry: Usually found either with heavy cavalry or with the light infantry/heavy infantry/militia/archers etc poptypes, light cavalry are mounted archers with a spear, similar to horse tribe but slightly different gear. What is different about them and horse tribe is that due to them coming in smaller numbers as part of other poptypes, they tend to be less of an issue - by the time you hack through the enemy infantry or heavy cav and get to them, they are not going to be a problem. Again they tend to be better against unarmoured guys vulnerable to arrows, and guys with low atk scores, but usually not enough so to matter.
Heavy Cav: Heavy cavalry's initial lance charge can be a danger to expander gods relying on protection, likewise it can delete expansion parties formed of a small number of sacreds. Heavy cav are often 'left til later', like large barb clumps, and sometimes people will create a small number of extremely low value guys purely to put in front and soak the initial lance charge - like local tribals, or national militia units - allowing the regular expander troops behind to cut the heavy cav down after they've used up their powerful lance attack. Combination of shield, reasonable defence, and being on a horse means heavy cav can beat up some kinds of national infantry even after they use their lance, although they tend to come in numbers like 7, 8, and a very large group of them might be 15.
All's Fair In Love And War
Generally you'll use a more general method of expanding. But sometimes you are The Cool Guy and your nation has some kind of Special Sauce that can make your expansion cooler and sexier.
Roman Expansion: Roman infantry (legionnaires, hastatus etc) expand pretty okay against most indie types with their javelins and shields. But most nations with roman infantry also have Gladiators (glads, retiarus, etc). These units are granted their freedom once they score a kill, but are very cheap in terms of recpoints, resources, and gold for how great they are. With the typical 'roman expansion' using prod and order and roman infantry, you buy gladiators, keep them on 'hold and attack' in the very rear, with some of their number up front in front of your roman infantry in small numbers. They die, or earn their freedom, then you cycle up another group of 7 or 8 to stand in front for the next fight. By having someone to tank while your guys toss javelins, and using the superhuman fighting skills of the gladiators to take out infantry, tank lances etc, you expand very well with fewer units than normal.
The vanir are superior to humans in every way: Vans & Helhirdings expand extremely well, but with orders to hold attack closest placed in the very rear, with a blood surge + 1x +def bless (you will also want Poison Resistance for fighting players later, and potentially a full resist bless) a group of 4-5 with a vanherse/helherse leading them can casually expand into most indie types losslessly. Combine with their high mobility and you can achieve truly elf-worthy expansions with them. Applies to a lesser degree to all other cavalry sacreds who often need more stats to do it.
Early point buffing: A relatively difficult technique, this involves unlocking an early small-aoe buff spell (usually Protection (the spell, aoe 1 barkskin) or Luck) very early and using it to make infantry, cavalry, or sacreds much tougher than they usually are without the cost of a large awake bless. Can combine heavy prod and order with the effects of a powerful bless, at the cost of some micro in setting up the groups and the difficulty of getting the timing right for the early research to be in time for expansion.
Mixed elephant groups: Putting a few elephants or mammoths into a squad of high morale infantry is great for using these expensive guys for expansion without them routing due to small squad size. High morale sacreds are great for this, or anyone who isn't going to get stabbed and scare the elephants with their death. Works especially well with Mairya Warriors and Mammoths as EA Caelum. Notably elephants walk pretty fast, so putting them too far away from the enemy can result in the elephants diving the enemy by themselves and getting cut to pieces. Full front + hold and attack is often the script used.
Sometimes You Have To Pick Which Person In The Room To Kill
In general you will want to take out the easiest provinces first, unless your dominion spreads to notice a juicy high population province that is enough difference in income to grab even at the cost of a few more casualties. Taking weak provinces gives you vision and access on more provinces, allows you to expand faster by taking on more weak provinces, and giving you access to weakly defended high income provinces (high income but with militia/light infantry is going to be easier than low income but defended by Heavy Cavalry - not always, but often).
However sometimes you will want to depart from this mode, generally for the following reasons.
Beelining: Some nations need certain terrain types, which can be rare. Wastes, highlands/mountains, forests, caves, coasts. The kinds that can make or break your game are usually wastes (for se'ir summoning), caves (largely for MA xibalba to get camazotz), or coasts (for many nations that rely on coastal-recruit-only mages), as forests and highland/mountains are very common on most maps. Going straight for one of those province types can be worthwhile as those nations, if you don't start with one nearby.
Snaking: Typically you will expand radially, as the weakest provinces are rarely in a straight line. But snaking (expanding in a single straight line direction across the map) can 'cut off' enemy expansion from areas that you want. Usually this is done with an awake expander, or highly powerful expander sacreds, but infantry that are good at fighting indies can accomplish this. Snaking can cut off a chokepoint, block a river crossing, or give access to a cluster of high income provinces (or even cut enemies off from the same, if you can't yet take them).
Cap circle: Provinces adjacent to your capital (cap circle) will give your capital extra Resources to spend on troops once they are in your hands. Prioritizing taking them can allow resource heavy troops to be produced in higher numbers, potentially increasing the number of expansion parties you can make during expansion by securing them first.
Whether you utilize these methods or simply go for weakest enemy provinces depends on what forces you have, your judgement of the strength difference between the enemy provinces, and what unit types your troops are effective against. Like all expansion strategies, these judgements can be practiced in singleplayer, but snaking and beelining are both strategies that rely on anticipating, noticing, and stopping other players' movements so to some degree will always require mp experience to perfect.
The 'shape' you expand to will in many ways determine the political geography of the later stages of the game. Aggressively creating beachheads with one neighbour might make war inevitable - taking conservative positions along a river bank may discourage a foe from attacking over heavily defended bridge crossings. The course of the map, high connection provinces you might want to fort, chokepoints, mountain crossings, river crossings, province types, province sizes and incomes, all of this can and should factor into your decisions on which indies to take on next with what force - and when you want to send a beefed up expansion party intended to go the distance, and when you're fine just taking one province with what you've got on hand.
You Can Dance - But Can You Dance With The Giant Snake?
Certain independents are special. Luckily, that usually means you get access to SWEET INDIE MAGES. Unluckily, they can be tough to kill, and sometimes inconveniently in the way.
Jade Amazons: By far the most common type of amazons, jade amazons consist of motivated spearmen and mounted elite light cavalry mounted on lizards with two attacks. Luckily they usually don't have too many of the oiorpata-alike cavalry, and the spearmen aren't heavily armoured. Most of the strategies that work on provinces with piles of light infantry work on these guys, but watch out for the jade maidens as they ride very quickly and can end up hitting your rear. Allows you to recruit Jade Sorceresses, who, being n1w1, can be given a thistle mace (forged by a n2, potentially empowered from n1) to cast foul vapours, making them hilariously effective if the enemy is not expecting it.
Lizards: Trident and bite attack predator lizard infantry (unarmoured), one shaman. These guys flood across the field in a block and hit really hard and a lot of times. Like barbs but moreso. They don't hit quite as hard as barbs (the secondary bite attack is pretty weaksauce too) but they are still more dangerous. However they are somehow even more vulnerable to ranged attacks, as they think armour is for sissies. Definitely want to wipe them fast, not get into a slugging match. Their huge number of attacks can pull down defence-reliant troops. You get lizard shamans there, s1n1 mages that are VERY useful for a variety of astral and nature tasks, notably being able to communion to cast Poison Ward or serpent's blessing without needing nature boosters.
Crystal Amazons: Probably the easiest of the amazons, these archer ladies don't wear armour and their pegasus riders don't attack rear but rather fire shortbows. Most any infantry can walk across the field and stab them to death, although small groups might get in melee with pegasus riders and lose in some crappy situation. Allows you to recruit s1a1 mages, which are AMAZING, being able to communion up and cast all the high air buffs people struggle with. Pegasus riders are too expensive to use generally, even if you luck into them when you have a bless that suits.
Statues & Stone Monstras: Avoid. Super hard. Harder than most thrones. Don't give you anything special.
Onyx Amazons: Fear cavalry and good medium infantry. The cavalry have huge enc and are fragile, so tend to die before their fear does much. The infantry are solid though, and take a bit of killing. The mage you can recruit from them is e1d1, not a great combo, but e1 is useful as E access if you have none.
Bone Tribe: Tough in melee, javelins, rough customers all around. Elite tribal infantry. Archery can work on them if you have piles of archers for some reason (?). In general, heavyish infantry in numbers or a larger than normal contingent of elites will be required to take these guys down. You get a d1 + e1 or a1 mage out of them, which is better than it sounds. E1 is good E access if you have none, but also e1 makes lightning rods, and a1 makes storm spools, and d1a1 with a lightning rod and storm spool can make corpse constructs at 6 per 1 gem. Corpse constructs (led by mound kings, say) are excellent chaff and a boon to any nation that can make them.
Knights: Improved heavy cavalry, they also come with longbowmen. If you want to point buff guys but don't have good guys to buff, knights can be worth buying. The commanders are nice if you're making cheap indie commander thugs. Everything you do vs heavy cavalry (lance catching, bogging them down) applies to these guys but moreso.