1) Get a full length mirror you can stand in front of. This is a great way to see your own form. Where is that elbow? Where are your feet? At the end of your legs, I hope. How are you holding your head? You can't see yourself as others do, but a mirror is better than a friend, it won't lie to you.
2) Keep a journal. Each day you shoot, debrief yourself. Write down your impressions of what worked or didn't work. Read your notes and think about those observations. If you don't shoot every day, notes will refresh your mind to what you're working on as you build a repeatable shot sequence.
3) Take your movie camera once in a while and record your shot sequence. A picture is worth a thousand words, and you will see how terrible your form really is. Once you see the problems you can begin to work on them. Smile at the camera, you're becoming a work of art.
4) Take a picture of every group you make. You can study your groups and eventually see patterns like usually left and high or perhaps right and low. When you become aware of where your shots are falling you can go back and work on your form to correct this. If you're not aware of your shot pattern you will only keep doing the same thing that causes the problem.