A basic guide suggesting a team composition, equipment and skill builds for newer players.
First and foremost don't let this guide tell you how to play. Play however you like and be sure to try new combinations. All that matters is to have fun. This guide is just my opinion on how the most optimal team composition looks like.
These 2 are the core of the party. They are hard to replace and will carry you throughout the entire game. Make sure you get them as soon as possible so that you don't have to worry about them falling behind in XP
Jock - Dwarf - Warrior
Why Jock? Because he has the highest Body stat and an extra arm slot can be super useful. The three-handed sword can be found pretty early and used only by him. It's very strong and severely outdamages any other weapon at that point of the game all the way until you can make +3 enchantments.
Why Dwarf? More points in Body and a racial ability giving more damage reduction.
Why Warrior? In combination with your character and race this class makes an excellent tank that doesn't lack damage. Max out Power Lunge first and then Riposte second. If you want to you can put 1 point into Riposte and Pommel strike early on for more support/utility. Cleave is not recommended as it does very little damage and requires a lot of level investment to make it viable.
Lab Rat - Human - Mage
Why Lab Rat? Because he has the Highest Mind stat and an extra trinket slot make him a very powerful caster.
Why Human? An extra skill point gives the mage a much needed headstart. This is far better than elves' 20 extra energy.
Why Mage? This class is strong at any point in the game. They have the strongest AoE spell that also scales with spell damage (unlike hunter for example). Max out Chain Lightning first and Arcane Flow second. Putting points in Fireball is a waste imo because status effects can be easily dispelled at the beginning of every round. Same for Frostbite - can be resisted easily, especially by the late game bosses. If you have Fist of Fury DLC you can find a certain trinket that will add 1 level to each ability, meaning you can have at least 1 point in each ability without any investment.
The rest of the team can be anything you want. But I suggest these 3 classes as they work really well.
Rocker - Dwarf - Paladin
Why Rocker? Rocker's passive ability removes the negative effects of armors and shields, making him possibly the best tank in the game. It also synergizes well with Paladin's passive ability, which I will talk about shortly.
Why Dwarf? Both Dwarf and Human work well with Paladin. It's up to you to choose which one. Human gets a skill point earlier, Dwarf gets higher chance to resist stun and weakness. In terms of damage and tankiness they will be around the same.
Why Paladin? Paladin's passive ability allows him to use his Energy as Health. Combining that with the Rocker's passive makes this party member the best tank in the game. Put 1 point into Armor of Faith early on and put the rest either into Smite or Guiding Strike. The latter does a little bit more damage than Smite, costs less energy and gains threat, but it doesn't apply weakness to enemies. Once again it's up to you to decide which one to max out.
Who to replace with? Knight is basically the same as Paladin. The only downside of the Knight is that his only damaging skill depends on threat level. And the bigger the party, the less threat percentage he has. Overall though I can see him working out in a low-threat single tank party.
Cheerleader - Elf - Thief
Why Cheerleader? Cheerleader's passive is rather strong in the early and even mid-game. And it happens to work well with Thief's passive which I will talk about soon. Later in the game thought you can replace her with Rich Kid for more Sense stat.
Why Elf? Higher initiative and crit chance as well as better resist rolls and camping rolls. Overall though situation is the same as paladin - you can go with either Elf of Human. Take the latter if you like that extra skill point.
Why Thief? High burst damage, low threat, ability to re-position the enemies and even AoE damage potential - this makes the Thief one of the best classes in the game. The passive, Stealth, also can turn the Thief into a party healer, thanks to Cheerleader's innate ability. Put 1 point into Stealth and Grappling Hook early on, the rest goes into Backstab. Barrage of Knives works well if you have a lot of status applying members, but I personally prefer leaving the AoE damage to the Mage.
Possible replacements? Hunter and Ninja. While the Thief excels in faster battles, the Hunter works better in longer fights. Overall though Hunter is outclassed both in burst damage and AoE. The Ninja however is pretty close to the Thief or probably even better. Their mass stun build, sudden death build or even just plain old Shadow Chain build can outshine any other class in the game with ease.
Hipster - Human - Cleric
Why Hipster? Unlocking items in the shop early is very useful, especially the enchantment scrolls. Later in the game however you can replace him with Surfer to worry about 1 less condition or Bookworm if you are going for an achievement.
Why Human? Because as a Cleric you don't have to worry about crits, initiative, threat, damage and etc. All they care is them skill points. And a bonus Mind stat means better resistance to Rage and Confusion which can screw up the Cleric.
Why Cleric? After you're done adding tanks and damage dealers to the party, it's time to add a support character. Just healing your wounded party members (and recovering their Energy while you're at it) can be very impactful. Try to keep your level of Restoration at a point where it heals at least half of your tank's health. The rest goes into Radiance (this is especially useful for Paladin and Mage). If you want to you can put 1 or 3 points in Purge to recover from 1 or 2 conditions respectively, but that's the only use for it as it heals very little and costs a lot of energy.
Replacements? As a support Cleric is the best class out there, but Warlock and Druid have those capabilities too. Warlock can heal even more than cleric with Life Transfer, which also damages enemies. 1 point in Renewing Carapace for Druid is also not bad. But if you are trying to replace the Cleric you probably don't need a support. In which case any class is ok. Warlock and Psion have a strong burst single target spell that scales with spell damage. Ninja and Druid have a lot of utility with their mass stun inflicting spells. And Barbarian, Monk and Knight have high burst damage spells that scale with physical damage.
Weapons and Armor (Shop)
Self explanatory. Safe to purchase for Warrior, Paladin, Thief and even Cleric. I recommend waiting until you unlock heavy armor instead of buying light/medium armor earlier, but if you got the money - go for it.
Safe to buy for Warrior and Paladin. The reason I go for Maul over Waraxe is stun. Yes, your crit chance is low but when you do crit you will stun an enemy without any resist rolls, be it a rat trap or a dragon. Stunned enemies also automatically lose all their resist rolls for other conditions which makes it the strongest condition in the game.
Safe to buy for Cleric, Mage and even Thief. The same reason as maul, but this thing has no threat and later can be crafted into Magic Staff and Staff of Ro.
Optional for Thief. Dirt cheap and adds a lot of crit chance.
Another option for Thief. Buy this if you don't want to spend a skill point on Grappling Hook.
A better alternative for bow. Frees up a hand slot for anything else. Found in the Orienting village (Fist of Fury DLC).
Optional for Warrior (Jock) to use alongside with maul for extra tankiness.
Optional for Warrior (Jock) to use alongside with maul for extra damage. Or for Paladin if you want him to use a shield.
At least 1 wand is safe to purchase. Later in the game will be used for crafting a Magic Staff.
Mind, Body and Senses rings. Safe to buy for Warrior, Paladin, Cleric and Thief. Later all three can be combined into Almighty Ring that gives +1 to Body, Senses and Mind, meaning you can have up to 3 extra stats for each. This is especially good going into end-game content as it gives you better chances to resist all conditions while also boosting your camping rolls and higher chances to avoid dungeon traps. I recommend getting at least 1 Almighty ring for each party member (except the Mage) and fill out the rest of the trinket slots with relics you find along the storyline.
Basically a weaker version of the Almighty Ring. But used to craft another ring that increases damage against end-game bosses. Can be purchased in the Expandria Castle (Here be Dragons DLC).
The main source of damage for Mage. One is used for crafting a Magic Staff. Buy and equip four more if you want to maximize the damage of your Mage. At least 3 of them is safe to purchase.
Used for crafting the Staff of Ro. At least 1 is safe to purchase although it's unlocked pretty late into the game.
Below I will list a couple of strong relics that can be found by investigating areas. I will not list relics found via main quest because you will find them yourself eventually.
Found in the Graveyard. This weapon is slightly stronger than a +2 Greatsword and can be used only by the Jock. This will be his main weapon all the way until you unlock a +3 scroll in the shop.
A stun applied from hand via critical hit ignores resist rolls. This is where this trinket really shines. Equip it on your Warrior, Paladin or Cleric. It can be found at Spawn Point Village.
The only armor in the game without energy penalty. Can be found in the Vault.
Found in the Orienting Village (Fist of Fury DLC). Adds 1 level to all your skills, basically giving 4 free skill points. Best used on the Mage.
Another god-tier trinket for Mage. Found in the Monastery (Fist of Fury DLC).
Max out Power Lunge first and then Riposte second. You can put 1 point into Riposte and Pommel Strike early for some utlity. A maxed out Cleave does way less damage than Mage's Chain Lightning even with the highest damage setup.
Max out Chain Lightning First and then Arcane Flow second (but keep in mind that paper hat trinket adds 1 level to each). I do not recommend Frostbite and Fireball simply because Mage doesn't have any spare skill points.
Max out either Smite or Guiding Strike first. Both of them will do around the same damage. The only difference is Smite applies Weakness to almost all enemies and Guiding Strike gives Paladin extra threat. Put 1 point into Armor of Faith early and max it after you're done with Smite or Guiding Strike.
Max out Backstab first and then Grappling Hook second. Put 1 point into Stealth and Grappling Hook early. You can ignore the latter if you chose to use the bow or shuriken or simply don't want to line up your enemies for Mage's Chain Lightning.
The level of Restoration will fully depend on the health of your tanks. For starters put 3 points into it and start leveling up Radiance. When you notice that your Restoration is not doing enough start putting more levels to it. Overall Radiance and Restoration levels should be around the same. You can put 1 point into Purge when you feel like you need it.
The room setup that will carry you through the entire game.
Physics Project - Spell damage +2. Can be replaced with a Weapon Rack if you are going for the Sudden Death Ninja build.
Bearskin Rug - Health +20. Can be replaced with a Bamboo Yoga Mat later in the game where 20 health doesn't matter as much as resist rolls.
Royal Chair - Energy +20. Can be replaced with a Red Sofa for more damage or Black Leather Sofa for more damage reduction if you feel like 20 energy is not useful
Light Gun Arcade - Your basic attacks deal 5 more damage at the cost of 5 energy. If you feel like you're not doing a lot of basic attacks, you can replace it with a Pinball arcade
Bowling set - 5% extra XP. Can be replaced with Race Car Track if you're struggling in the dungeons.
Golden Table - Charms become available as item drops. This decor is too important to replace in my opinion as charms cannot be obtained normally from enemy drops. And Pounds of Rock (aka Geodes) are a real pain to get.
Dice Collection - Dwarves get +1 Body, Elves +1 Senses and Humans +1 Mind. Can be replaced with Go Set if you're doing Barrage of Knives and/or mass stun Ninja shenanigans.