What can I do to prepare my red/ brown hair to be colored blonde?

I'm hoping for the Cameron Diaz look in the Mask. I've been doing deep conditioning and re constructive treatments but I want to slowly lighten my color until I feel I'm ready to do the drastic. I also don't want my hair to fall off when I go blonde, so I want to lighten it slowly but surely. Any advise? Besides burning it in the sun?