One of the things you can do is to get into a good golf posture (have someone confirm or look into a mirror) and get two alignment sticks (you can get them at your local big box home improvement stores-they're called driveway markers or mailbox markers).  Put one alignment stick in the ground and in contact with your right hip and the other at the same point off your left hip.  When you turn back, make sure your right hip stays in contact throughout your backswing and on your downswing, make sure your left hip stays in contact with the other alignment stick.  This will help maintain your posture and spine angle throughout your swing.  If you need more, you can also have someone hold a club against your head throughout your swing so that you get biofeedback on head motion.

Thanks. I am left handed so I would assume that I would do everything the same but on the opposite hip.

The problem with most amature's setup is that their posture is way to strenuous and robotic. When your body is tense this will interm cause your movements swing to be jerky and unnatural. This movement could be any thing from the head moving to close to the ball to hands droping to far inside. If your setup feels unnatural try relaxing your body. What you should is make sure your shoulders are not to pushed back and that they roll foward and hang there(without having your back hunched). From there you just let your arms hang down. I'm sure you'll notice this will fix your problem of being to upright and the head movement.

iziah nailed it!!