Hi there! I've recently taken interest into digital drawings, moving from paper art to pen and tablet. However, I'm having a bit of a problem doing certain things...

http://4.bp.blogspot.com/-UYK4ZsCt5A...Garage+wip.jpg - I'd be really thankful if someone can explain how I can do the 2 to 3 pics. I see the artist paints over with color, but then how can I make it stay in shape and not just messed up everywhere? Do I erase it? Do I mask it somehow or overlay? As you can see in pic2, the colors are everywhere while in pic 3, they take defined shapes. While I sometimes like working messy, what can I do to keep colors in a contour?

Any other tutorial or help is welcomed!