Spent the early part of the game making money by selling bandits. They're 130 per and you can easily fill up your limit by having a party consisting of only the manhunter line. With the manhunter bonus I could have 35 prisoners max, netting about 4550 per haul.

I also spent a lot of time early on building relationships with all the lords but I realize that's a waste of time now. Good lords (upstanding, good natured) will automatically have their relationship with you raised as you gain honor. Bad lords (debauched, quarrelsome, pitiless) are not worth having in your eventual kingdom so don't bother. Martial/calculating are easy enough to keep happy just through domestic policy, good fief management (+10 per fief, also get a boost if you give a fief to someone he approves of), and liberal application of marshalhood (new martial gets +5, all of his allies get +1, enemies get -1).

I eventually built up enough renown (very important - higher renown means a larger party. Lords are also more likely to follow you and obey your orders if you have high renown) that Doge Graveth offered me a vassalage. I took it and started ramping up building relationships with villages at this point. Vaegir/nord villages are great since those two are right next to each other and have the best archers/infantry respectively. Swadian villages at the center of the map are great because they're easy to get to. I didn't bother with khergit/sarranid villages since I knew they'd be pretty far from my starting point.

I made sure to build my relationship with Doge Graveth at this point too so I could get more fiefs. It isn't very hard. You get +1 with your king every time you do anything good and talk to him.

When I thought I was ready I struck out on my own and took Reyvadin, requested it, and got it. Garrisoned my slaver chief army and started training up only vaegir A6s, Nord I6s, and Swadian C6s (those are the best btw. Found out later that Rhodok crossbowmen are amazing for defense. They're very well armored and use a sword and shield in melee making them very competent if you need to use them to block off entrances). Later realized that any tier 5 unit is already plenty good enough and stopped training those three exclusively but I didn't at the time. After I built up a large enough stack of those three I started taking the nearby castles as well. I think I managed to take/request/get 2 or 3 castles before my good relationship with Doge Graveth was finally not enough to make him give me the castle. That's when I rebelled.

I had enough villages from the town + 3 castles in my new kingdom that I could give them out to all the good/martial/calculating lords who wanted to join my new kingdom. I had a high enough right to rule that nobody mobbed me right away either (that or a rebellion doesn't make everyone mob you, not sure). I did still get mobbed later on but that wasn't till quite a bit later. A bunch of lords that were close to me flipped as well. A couple I talked to rebelled with me as well. Not a whole lot, but enough to start a kingdom.

Started using my built up stack to take more towns/castles until the Rhodoks sued for peace. I needed a breather to consolidate and accepted. Around this time is when I realized a crappy garrison is good enough (my stack of good men was running low and I couldn't recruit/train fast enough to replace them), and that rescuing prisoners from bandits is a good way to get junk garrisons. I've never bothered before since I wanted only vaegir/nords/swadian. Soooo much wasted potential men. My army becomes a very ragtag bunch at this point. I also stopped relying so much on cavalry after realizing how powerful just archers + infantry were and at the fraction of a cost of a pure cavalry army.

Eventually got tag teamed by Nords, Swadians and Vaegirs. Had a bunch of the Nords flip to me with castles (that was nice) as soon as the war started. I took out the Vaegirs, made peace with the nords to focus on the swadians, and then took them out. That was the last time I accepted a peace deal. All other times - as soon as anyone declared war on me we were fighting till the extinction.

I think by this point I had so many lords that new ones stopped showing up in my court. I had to actually go recruit lords to join if I wanted new ones. Around this time is when I started a system of a small group of good men with me and amassing junk men in border towns and using them to fill up new castles/towns that I took. Eventually took out the Nords, then Rhodoks. The Khergits had wiped out all the Sarranids (except for one town) at this point so it was basically a showdown between us. This is also about the point when I decided to just start hoarding fiefs and doing everything on my own so I didn't have to keep on waiting for my lords to show up. They were probably the easiest to beat in sieges. Steamrolled them and eventually took the whole map after a long, long war where they kept trying to sue for peace.