This...do 1v1s or 2v2s, larger maps are not very good for learning...the greatest weakness of most new playes is their expansion, it just isn't fast enough and from then on they are always behind and everything is an uphill battle....larger maps penalize you even more for expanding slower, because you are closer to your enemies (less planets per player on larger maps) and enemies far from you can potentially wipe out other players and become behemoths late game...
Personally, right now I think Vasari Rebels are the easiest to play as for noobs...phase stabilizers can let you jump anywhere, and the phase jumping SBs makes offensive actions much easier...also, the moving SB in general just helps you defend better against the AI...these two elements allow you to defend and attack anywhere, which is invaluable when you are having a hard time dealing with multiple AIs attacking you....
I generally suggest that one should be capable of dealing with unfair AIs before moving to MP...that being said, regardless of what difficulty you are comfortable with, your first MP games should probably be with other newer players on smaller maps...
