when you settle in the northern location (4/3/2 tile), it's possible to get two more cities to the south on the river (i put one on the bend of the river on a 3/4/0 tile with forest and a nearby clay pit (this became my main fortress), and this location allowed me to settle a decent town on the western end of the river (5/3/0 tile). those 3 cities should be enough to get you started; clear the ogre(or troll?)/mire skath lair near the second city soon, behind them you find 2 gold mines.
when you spread north, you can plop another 1-2 decent cities on near the northern river (halfway between tarth and carrodus). you have to kill a river slag for the second city (lost my starting spearman and militia in that fight grrr).
combat wise, i picked the defender unit, later got the panca archers and made my first champion a defender (my relias was a warrior in that game); with two brickwalls, some range dps and a powerful warrior champ, the syndicate clowns were a cakewalk. once my fortress was done with the basic production and training buildings, i built a few custom spearmen and conquered the yithril enclave. i probably could have started my invasion at that point, but i decided to explore the western continent for a while first and get at least daggers and bows 
don't forget to sign trade and economy treaties with your allies (especially the trade treaties - 40% boost to your income is huge); and sign non aggression pacts when they are willing to give you cash for it. when you get to literacy, also sign tech treaties (2-3 coclaves with the 40% boost from 4 tech treaties will get you trhough the relevant parts of the each tree in no time)
after fooling around for a while, i filled up the armies of my champions with new short sowrdsmen and longbow archers and started my invasion; along the way, i picked up longsowrds and later yew bows. resources seem rather scarce on this map, so designing units that don't require much iron/crystal seemed like a good plan. my main designs were swordsmen (to serve as "tanks") whith best sword/best shield, full leather armor, defensive, finesse, ironskin; and archers with accuracy and fury (and one of the dodge traits i think) i gave the archers soldiers boots & gloves, otherwise full leather armor. i had 3 full amries of those units (initially at army size 4, later upgraded to 5/6)
by the time i killed of resoln and kraxis, my units were pretty much fully upgraded and i was done with civ and warfare tech, so i filled the magic tree next; spell of making (for titans' call - great for getting reinforcments to the other continent!) and third book (for the starfall strategic spell) were quite useful for the seemingly endless waves of yithril juggernauts and useless slave armies.
won't spoil the end of the campaign. if you make it that far, the game is won anyway - you just have to conclude it.