When she's right I tell her so and when I'm right she does the same.
When it's simply a matter of opinion or preference we negotiate. I don't feel the need to be right (even when I am) all of the time.
We are both old enough to know that life is too short to let little disagreements get the best of us.
This isnt really a strategy but I don't really bring anything up unless I am going to blow up about it because at that point I know its not just a little pet peeve but something that I need to talk about. I guess pick your battles.