Click Here to Bid (6x6in. - starts at $100)
Before I did this one, I painted some quick, 10-minute tomatoes (to the right). I ALWAYS learn a lot from them, even if I've been painting lots of this subject anyway. And it's because I know they won't be "finished" (or saleable) and so I experiment. We aren't learning new things unless we're TRYING new things.
In other words, if we always do what we always do, we'll always get what we always get.
So pull out a spare panel, divide it into smaller parts, and try sh*t. Do it today. Then show a friend. Tell them what you learned. It doesn't have to be something HUGE! You'll learn tiny little things that you can apply to the next one, times four.