How do you get a mean sister back?

By being as nice as you can. Example: If your sister insults you, simply smile and say "I am sorry you feel that way". Or kindly ask "Why do you feel the need to be so rude". Then you are the bigger person, and a lot of the time people are only mean to get a reaction out of someone. Dont give her that.

That is a great answer, but just tell her how you feel in other Words, instaed of sucking up t her. Don't let her take charge and just stay away from her if all else fails, because she might just end up being not as pitiless and will miss you. She loves you and always will. Just remember that.