Watch some of the games of the top bots. One thing I haven't seen a top bot do yet is identify situations where they have an impasse (e.g., three ants holding off an entire horde) and try another route.
I've been doing that, it's interesting indeed, thanks : I probably won't have the time to make a good enough bot to compete with the top of the top, but I'll do what I can.
Aichallenge.org has started their third AI contest this year: Ants.
I mentioned this in the open thread, and there was a discussion about possibly making one or more "official" LessWrong teams. D_Alex has offered a motivational prize. If this interests you, please discuss in the comments!