Analyzing your swing

When analyzing a swing I pay attention to four things, trajectory of the shot, curvature of the shot, what area of the clubface the ball hits, and what happens at impact.  Regardless of the player, if they're not hitting the ball the way they would like, one or more of those areas are at fault.  I let those categories tell me where to start in the swing.
For example if you're hitting the ball on the toe of the club here's your choices.  You're too far from the ball at address, getting further from the ball at some point in the swing, swinging the club too much inside the ball on the downswing or your clubs are either too short or too flat.  There's one hook tendency that results from your right hand hit over your left hand which causes a toe hit and a toe hook.  Those are your options.
I let the student make enough swings for me to exhaust all these possibilities before I make my correction.  This procedure allows me to make the correct diagnosis every time.  It also allows me to get some immediate relief to the students bad shots.  The consistency of the correction might take a little time but the student can sense there's relief in sight.
It's not easy to self diagnose your golf swing but if you follow the above steps you'll certainly be moving in the right direction.