I guess it is hit or miss, I have played games where the AI was right next to me for over 200 turns and never once attacked me.
Checking their info, it states I got a +2 for outmatching them, and a +1 for having the same allegiance. Looking at this info I can assume that the AI will always attack if they think they can take you. Not sure how it is calculated, but I assume it goes off of your army's total combat value.
With the current Beta I try to get spells trained ASAP, and start off with the summoning skill. Summon a bear and a wildling as soon as possible, and use your lightning spell (currently kills most things). I then try to expand and train for archers. Archers with a short bow can shoot at least twice per turn, doing approx 11 damage each shot. (I know most of this will be changed very soon) Currently I have not had any problem wiping the AI out with 2 archers, 3 summons and my spell casting SOV. I am able to wipe out most armies on the first turn.
My biggest problem is managing my gold scheme. I want to aggressively expand, but that leaves me with little gold for recruiting. I by no means consider this a bad thing, it should be a balancing act and not easy to buy everything you want.
With the current build, you will not need knights or heavy troops, archers with no armor will do just fine. No need to build a 250+ gold knight that will take damage from a 20 gold foot soldier.
Hope this helps you get a few more turns into the beta, but I would not put too much faith in it, as I am sure things will massively change on the next release. Knowing Stardock I expect there to be very few "I win" strategies once the final version comes out.
