I am an admirer of Duaine Keiser of Virginia who does 'A Painting A Day' blog here on Blogspot. How you get really good is to paint 'miles of canvas' to quote an influential teacher of mine. This painting is approximately 6x8. It needs a touch more 'tweaking' but it's going to turn out well.
Go to my links and click on When I Grow up to find Duaine's blog. He's inspirational to artists like me who procrastinate too much.