Thanks guys!
I have been reading posts about Killer's games for the last couple of weeks. Skyfish, you're right, a definite theme emerges
When I play single player games I tend to play more of a builder style, so I'll definitely have to change my style somewhat. I've also picked up a few things from reading posts that I haven't had to worry about in single player. A common one seems to be bribing AI's into MA's against other human opponents. Are there any other multiplayer tricks I should watch out for?