I took a Color Theory class in college and all we did was water color, I might still have my brushes lying around. I'll see if I can find the sizes/type for ya.
What kind are you using? I
think we used this paint (it's been 3+ years):
Savoir Faire Opaque Watercolor Set
I am by no means artistic and it was my first time ever using this kind of paint. I found it very easy to mix and get nice color gradients. Michaels has more expensive stuff that may be better for you but I wasn't willing to spend the doe, we did A LOT of projects and I wasted paint like a maniac.