There's of course the "Same person you hate so you gang up to go kill him." technique as well. There's a certain plot involving a loth from a past game that comes to mind for that.
The big trick is to make sure the *players* understand that you expect them to keep the conflict in game only, and that they're expected to get along in the end - they can just make a good story out of it along the way to that end. The only reason players are allowed to do this sort of thing is for the story, so they better make it a good one.
That's how my current group gets along, characters range from LG to an NE bordering on CE. We all, as players, want to enjoy the game and make sure our friends do too so we find good reasons to work together. It helps that the party leader is not one of the extremes, as he's pretty strongly LN and strict about not tolerating inner-party grudges. It also helps that our most obviously evil character said so straight out once we decided to form a group: 'You should know, I don't like the Upper Planes and they don't like me. I'm not gonna try to hide that because I anticipate working with you for quite some time. You guys are good at what you do, I appreciate competance. And I appreciate money. So I think we'll get along.'

We've worn off on her since.
A few key beliefs have let us pull this off:
1) The idea of 'small to big' evil or good or whatever else for that matter. A slightly evil mortal is much easier to work with than a horrifically evil fiend.
2) Being all LG is as much about redemption as it is punishment. So not all evil should be approached with a burning stake.
3) Evil people have friends *too*. (And wow can evil people be protective of friends they consider 'innocent and naive', even if they never let said friends know how much they're going around threatening dire harm to any who would harm their friend...

)
A smart evil character will quickly realize that keeping his/her friends makes them stronger in the long run. Without friends, no one's around to retrieve your body when/if something ganks you, for example. And it can be good to have reliable people backing you, that you don't have to constantly check over your shoulder in dealing with. People you can actually trust. So long as the friends are not overly pushy in their own ways - things work out in the long run. Especially if you make a point of demonstrating that you aren't going to turn on your friends for both logical and emotional attachment reasons.