depends on what she is doing. But set boundaries and instist, in a loving but firm way, that she respects them. If she is not willing or able, you may have to accept that she is evil and just put up with it and not take it personally.
I just ignore mine and refuse to be around her.
Look her square in the eye and say "You do not run this show. Be nice or I'll have security escort you out." When she splutters.... yell loudly "Security .... Trouble down front!"
I was lucky to have had a great mother in law and father in law. But if I didn't get along with them I would just avoid them as much as possible.
The easiest way is just get divorced.
Tell her to stop being a biitch. Thats what I'd do .:)
I would do the opposite of Tgilly. I would be myself.. and if for some stupid *** reason that ****** her off or if she tries to be a b1tch, I would be a b1tch back. Fck her.
Spend as little time with her as possible and most importantly DON' T **** HER OFF !!
cut the brake lines on her broom
marry someone else :]