If you are planning on going anytime between now and say, mid April, I thought I'd share my tips, and ask you to share yours!
Expect it to be busy, and don't get frustrated because it is.
Do things you normally don't do. For example, yesterday I was hanging with my alterna wife and we enjoyed ourselves immensely despite the crowds.
We saw Golden Dreams. We sat and talked outside the Grand Ca. pool gates next to the garden. We rode Pooh. We did lots of shopping.
Just have a great time, regardless of there being a 40 minute line for Pirates, or the fact that all of the Faspasses for Space were all doled out before 11am.
If the line for the trams are crazy, walk it! It's really not that far of a walk and it's good for you! Yes, even after a full day or walking, a nice brisk walk before you drive home will get the blood pumping so you are ready to deal with the SoCal drivers out there.
Your favorite place to eat crazy crowded? Find a new place to eat. Go to the hotels and eat there. Have meals at off times. Try a snack around noon and then have linner (lunch/dinner) around 3:30/4:00.
Whatever you do, don't get mad, or frustrated, or pi$$ed off. Accept that it is going to be probably incredibly crowded the day you decide to go. Think of the worst possible scenerios. Then when you get there and see that the parks might actually NOT be as bad as you anticipted, you'll be a happy camper even moreso!