My personal favorite is green tea because it not only hydrates it also boost your metabolism. I have my drinking green tea for years now and have defiantly seen a difference in the way I burn calories as well as the way my skin looks.
You need half your body weight in ounces of water/tea (juice and soda don't count)
If you commit to filling your body with the nutrients it need then it will work better for you i.e. burn calories! Good luck Fit Girl.