First of all, starting with a good shampoo/conditioner...
Lately, I've been using Pureology shampoo and conditioner. This entire line is meant for colored hair and have a few different types, whether you want a volumizing or some serious hydration. Since I tend to have fine/flat hair, I like to use volumizing products, but most volumizing shampoos aren't meant for colored hair (this is why I love this line)From the grocery store, I really like L'Oreal's EverPure line... It's not expensive and I think it also works really well.
For the majority of shampoos and conditioners, always read to find if it says "safe for colored-treated hair" if it doesn't, it might not be the best choice.
One product that I have used since I was a freshman @ Baylor, is Bumble and Bumble's color support conditioner. I use it about 2-3 times a week and I can tell a difference when I don't use it. I use the one for 'cool blondes'The last product I want to tell you about has become an every day necesssity for me. I put it on right before I blow-dry my hair and it makes blow-drying a breeze! and it smells really good which is a plus in my book. It's from Kerastase and it's their Chroma Thermique.
Long live your color!! :)