I'm definitely a combination of octopus and shark, with a hidden dark side of squid. I basically begin the game by deciding who will be my first enemy, and then go with that. I gradually talk to most of the players in the game, when it suits me, and I am an expert diplomat and Intel gatherer. I can usually rally anyone to fight against anyone.
By the end of the game, I have betrayed a number of my allies, although I usually keep at least one ally, the one who is most trustworthy. My mining strategy is take any mines I can, and drill all my mines in the last 48 hours of the game.
This strategy seems to work quite well. Out of the three games I have played, I won the first and the third, and got bronze in the second, (and I should have got silver).