I have one piece of advice for those want to roleplay a bad guy. Don't be an asshole! Especially if you want to keep rping that character as a bad guy. In my humble opinion, playing the villian is one of the hardest, if not the hardest role to play successfully. It takes a lot of thought, planning and cooperatation in order to pull off a crime and get away with it.
Let's say that you have come to the Deadwood sim with the decision to be a villian. Great! We need bad guys in order for the good guys to become heroes. Unfortunately the following usually is what happens:
Asshat Noname enters town and swaggers into the Gem Saloon. Those present are Clay Kungler, the mayor and his wife September as well as several other locals.
Asshat Noname: *walks into the Gem and looks around with a smirk on his face.*
Asshat Noname: *lights a cigar*
Claytanic Kungler: Howdy stranger, would you like a drink?
Asshat Noname: *turns to face Clay and notices September*
Asshat Noname: Yeah, gimme a drink. By the way how much do ya charge fer the whore? *indicates September*
Claytanic Kungler: Stranger, that is my wife. I suggest ya apolgize, then get the hell outta here.
Asshat Noname: Fuck you, *pulls his gun*
Claytanic Kungler:*pulls gun*
Asshat Noname: DW meter shows him dead
If all you want to do is have a shootout, then maybe this would be fun for the bad guy. However he has shown himself to be an idiot who just want to have combat. But for everyone else, this becomes boring and the would be bad guy quickly finds most people avoid him like the plague and he leaves out of frustration. Too bad really, but then Deadwood is not for everyone.
If you really want to play a bad guy, don't go out of your way to antagonize people. Build friendships. Yes, I said friendships. A real life villian will have those who care about him. Wife, mother, brothers, friends. In roleplay, you will need people who like you and will stand up for you when you need help. BlackJack is a character that intimidates a lot of people. this is due to the avatars size and appearence as well as how I play him. Yet, Black has friends. Clay and Dio are his partners and he considers them friends. Both have helped Black in the past.
To end this little session on my soapbox I leave you with this. When you decide to be a villian, think about what motivates him. Is it money? power? sex? what? something motivates him to do what he does. From that point, play the character to enhance your chances of gaining whatever it is you want. You need to also think about what kind of villian you are. Are a political hack? a thief? a confidence man? combination of those? It all comes down to planning your character, who and what he/she is and what he/she wants.