Just remember it goes like this:

1) Lawful evil-you are regimented in your beliefs that you deserve shit, whether or not people want to give it to you. That said, you see the value in allies and being predictable in your evilness
2) neutral evil-basically, if you got allies it's because they benefit you. Never forget that you're the most important person in the world
3) chaotic evil-basically, you can do what you want when you want and you never have to say sorry

Obviously some of these are dumbed down, some of these shade towards religion/cabal choices available, etc

Try playing an evil, it's fun. Just do it with flair, it will be easier to get into the RP.