Go with your gut

 Choose the star of the painting.  Glance back and forth at it while you are setting up.  Get a feeling for composition and colors.  Notice the big things and sometimes the rest of the painting will work itself out.  An autumn afternoon with one of those wonderful October skies provided inspiration for a quick study.

Why you choose to paint something

Never, ever forget what attracted you to paint something.  You will spend hours exploring the subject and it is easy to fall into a pit of diversions.  Staying faithful to the initial idea will produce a nice finished piece and convey the beauty that you saw.