Use school glue gel, salt, & liquid watercolor on watercolor paper. The glue makes the colors rise from the paper and the salt creates a 'starburst' look. Rubbing alcohol on wet water color is cool too.
How to paint a realistic eye with watercolor! There is a lot to learn here but it is also just fun to watch. And it would be neat to record my own painting process just to see what I do that I don't notice I'm doing.