Watercolor is one of my favorite mediums. It's best to let it do its thing. Fighting with it's natural ability to wander on paper is probably setting oneself up for a frustrating experience. I've recently completed a watercolor for a Sonoma County Christmas card, and had fun painting a loose watercolor fashion illustration.
Part of the fun of painting is to experiment and have fun. Which is what the creative process should be about primarily. The wine and grapes art will be on my Zazzle store and card stores in the coming week. I'll come back then to link to the products.