If you wanted to include the background in the shot, I would've gone with a much deeper field so that the background can be in focus. I didn't even realize it was a scarecrow. There is also a lot of contrast in the image, but not placed so that the subject contrasts the background. There is contrast within the background, and within the subject, so it's not immediately obvious where the eyes should go. As others have said, it's generally best to use bright spots to draw attention around the image, so being conscious of where the bright areas will end up will help you visualize effective compositions. I agree with Compaq's subtractive approach. Do what you can to remove from the frame everything that does not contribute to the shot. What contributes and what distracts depends on what you want the subject to be, and where you want the viewers eyes to go.