Read the AARs. There's some juicy stuff in there on tactics and ideas, depending on the writer they may be explicit or just give you the general concepts.
I do enjoy Keith's method of alternate wormhole assault. Either they'll come at you in pieces so you can retreat and mess with them again or they'll break the stalemate and run right into the waiting arms of your turret walls.
There's a number of minor tactics that added together make the difference. Experience will change how you play each time, sometimes at each world as you play through a game. If you've got 'x' issue and can't seem to find a way to break the puzzle, we'll be more than happy to help. In general though there's no master list of tricks, like you'd find in Starcraft Strategy forums or the like. The entire point of AI War is to force tactical choices due to variety. There's never the 'right' way. There's only the 'right way right now'.
