Some of the things I took away from the last game (others were probably too specific to the situation to be listed here). Maybe these will be of benefit to others:
1) Plans are simple to come by. A given plan is probably OK (unless its just plain wrong for the situation), the game is won or lost in the execution.
1A) know what your plan is and follow it, or at least intentionally stray from it according to the situation
2) Raid soft targets, avoid hard targets completely. (sounds easy but in practice it's not)
3) Observe your own bad habits objectively and purge them.
4) If you raid your opponents town, his army in the field will be less well managed (or completely immobile)
5) Think about the implications of the starting buildings on the map - preferably at an early stage when it's not so busy and you have time to think. This will often matter in the early mid-game and it's dumb to be surprised by them seven minutes into the game.

Hope these aren't too abstract and they help someone out.
Cheers,
Steve