Redken and L'oreal both have websites that have great "help" sections. There are a few common Q & A's that are already listed and an engine where you type in your questions and possible answers are pulled up. Both websites are easy to navigate.
The best way to take care of your hair after you dye it, well is to use good shampoo with UV protection, follow the instructions on the hair dye and to reapply color when the directions tell you.