At the address position of your golf swing, your eyes should be looking down on the golf ball and should be relatively level. Maintaining this position, during the whole swing, will encourage a more consistent impact position and better strikes on the golf ball.
As you swing back away from the golf ball, it is relatively common to see a golfer turning their head away from the ball and looking out of the corner of their eye. This will result in some inconsistent shots and could signifying an over rotation or over swing.
A great exercise to monitor this position would be to set up facing head on into a mirror and look up so you can see yourself face on. Now go ahead and make your backswing. If you notice that your front shoulder is turning and hitting your chin during the backswing, this could be the main reason why you turn your head, resulting in an un-level eye position at the top of your swing.
To correct this issue, focus on turning your front shoulder down and under your chin. If your front shoulder doesn't hit your chin, there should be no reason to move your chin, which should result in a more level eye position at the top of the backswing. This, in turn, should result in more consistent ball striking.