Maddman75:
Evil urban campaign, huh? Sounds like fun. Normally, the key to screwing over the other players is to gain their trust. This might be kind of tough in an evil campaign since you can't hide behind that fact that everyone assumes your character is "heroic" and a "good guy." Without trust, you'll have to go over their heads and nab yourself a trump card: the DM.
Is your DM a member of the opposite sex? If so, I'd suggest developing a romantic relationship with her.
In the likely event that your DM is a guy and you aren't willing to "go the extra mile" for your character's sake, you'll need some kind of leverage to get the DM on your side. Blackmail is probably your best bet. If you can get your hands on some information the DM wouldn't want to get out...then you are in like Flynn my friend. The DM will be afraid to make you angry and he'll let you get away with all kinds of stuff. Let your imagination run wild from there.
Finally, let me applaud you for choosing an arcane spell caster. A lot of new guys seem to think that being a rogue is the best way to screw over the other PCs. Me, I like the sheer versatility of wizards.
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drothgery-
You said it, man, not me. I won't admit to anything. Now Robert Jordan, he is most definitely on my side...