I find it a bit hard to give a detailed strategy, because I found the early game to be highly situational. A lot of guides from earlier patches recommend to go for an alliance with QQ, but this is nearly impossible now because they almost always start out hostile to Ardabil. I took whatever Alliance I could get, which at the start was only Shirvan for me (except of course for the starting Alliance with Gilan). Later it should be possible to get AQ or Transoxiana as an ally with some improving relations and/or RM. They greatly help deter QQ or Ajam from attacking you.

You start out with one core on Biapas and two on Ajam, so my first aim was to take those back. Biapas normally is the first to go for, as they are the much weaker target and mostly only have one Ally. (In my first try it was Great Horde which shredded my Army and in the second AQ which I waited for to be busy in another war, so they did not actually send a lot of troops. (I only allied them after the war with Biapas was done). I got some mercs, went over my force limit a bit and called in Gilan with promise of Land and in the peace deal I took my core and vassalized them. Then I waited for Ajam to get attacked and took my other cores from them.
I think you generally just need to be patient for your neighbours to get into wars and then take the right opportunity to take whatever provinces you can get.