This Guide is about making your game somewhat easier, allowing you to at least having a good amount of money before starting your conquest. It's Intended for those who have interest in trading, easier game in general and some small tips.
The Very Beginning
You're born into a wonderful world full of battles to have, but first as a lonesome trader you first have to spec all your points into intelligence, as much as commanding and leadership are the main way to go in this game for now you will not be fighting, but feel free to spend some points in both if want (commanding caps at 5 btw), to speed things up I recommend 2 points into trading and 2 into navigation (navigation is always worth it since you will really need it if you have 50+ soldiers in your party // with 90 troops and 5 of navigation you almost feel like a rock), trading for now at least gives you 6% reduce in all buying prices, and 6% increase on the selling side ( about 12% of extra profit may not seem like much but when you are dealing with products of high prices it really helps) and while a single point in inventory would be a neat idea idk if items really slow you down (from personal experience day 0-60 I didn't fell like it) but it's always be good to have.
The second thing is kinda painful, I know there are your beloved FCA recruits and your normal recruits, truth is they'll slow you down on you way of getting those big bucks, so get rid of them, disband them both, or if you're feeling that you really want to keep the FCA (they are good units) I guess you can, but keep in mind that you'll be spending money both with their upkeep and food besides slowing you down a bit on the world map (alone you don't have to worry about those and you are generally faster than any of the parties in the world map, you can alway reach to a neutral town or unit to make parties following you stop that nonsense).
The third thing to do is sell all your items (including equipped ones), the more money you start with the more profit you'll be able to get, if you do this you should have 2.553 (with those 2 points into trading) or something close to that.
Traveling and Trading
Now that we've got set up, first thing we need to do is find places with good demand items which are ranged generally from 131% - 144% in price increase ( I guess the range is 130-145 but I never seen those in demands so don't quote me on that ) scout the whole map for trading points, If by any means you got really bad demands (of items worth less than 200-300 // only a item or two worth more as a demand item) save and start a new campaign DON'T SAVE after starting a new campaign. (why? for now doing this and loading your game resets the demands as well as the units in the world map, being the only way to change demands -- loading only resets just troops around the world map not the demands. // The demands will always change when you close your game for now and as far as I'm aware demands don't change unless you close your game or start a new campaign.)
So now hopefully you may have scouted the world and found at least 3-4 settlements with goods worth trading you need to establish a trading route, the longer the better, since the merchants money resets everyday along the items they have, try to visit the settlements along the way to see if they have anything which you may get a profit along the way, I highly suggest that you don't fight any of the factions if you do wish to follow the Peaceful Trader step of this guide, which may be followed after your first 15-20k of earnings. This will be your game for as long as you want (I would recommend you keep on it until you at least can afford some good gear // grinding on enemies for now seems kinda not worth it since the only way you will get a good amount of money is sieges, and believe me those are harsh against the main factions) , personally with really bad demand and in a worst case scenario (bandit town being the only one which I could get a good profit - after paying them 500 to enter) it took me 30 days to get to 50k, with that amount you at least can get the best gear of the game: RPG, max armor (111), a good assault rifle (snipers may be what you are aiming for but from personal experience I just fell in love with the AR 41, good scope, fire rate, damage and not much of a bullet drop) and a pistol as your backup.
The Peaceful Trader
It's a good thing to keep your relations up (kinda of, as far as I am aware you'll have no benefit in relations higher than 0) at the beginning the factions that are in war with you are the Bandits and the Uman Brotherhood, every other faction will be neutral therefore they'll let your mind your business. Following the trading route and getting on good therms with at least of one of those bothersome factions can be really helpful, bandits seem to have more active parties while the uman have stronger (they are no joke) and sizeable parties, keep in mind that bandits are ever spawning while the uman depend on their settlement to spawn (in my campaign they are gone for good).
If you wish to follow the peaceful route (for now) as soon as you get your first 15k-20k pay tribute to those factions, with tributes you will lose 1k and get +10 of reputation as soon as you get the faction reputation to 0 they will stop being hostile towards you, if you fought at lot any of them this might be really costly, so not worth in my opinion. The benefits working with the diplomacy are just getting their settlements as trading routes without paying the 500 fee and safe travel around the world map.