It is a traditional belief that to hit the ball flush you need to shift the majority of your bodyweight to the right as you complete your backswing; shift it back to the left on the forward swing while keeping your head and upper body behind the ball through impact.
However, it's difficult to shift your bodyweight to the left side without allowing your head and upper body to move forward together with your bodyweight. Weight shift to the left foot at the start of the downswing hampers your staying behind the ball at impact.
To deal with this demanding business of staying behind the ball, it is as well to forget about the weight shift to the right on the backswing and to the left on the downswing.
Put the weight shift business out of your mind and think about gently kicking your right foot and knee toward the ball to initiate downswing or pushing hard off the inside of your right instep through impact.
That presents a better chance of shifting your bodyweight properly during the swing, enabling you to start downswing from the ground up.
That allows your right heel to correctly come off the ground just after impact, eliminating the over-the-top move.
That also ensures that you finish with most of your bodyweight on the outside of your left foot.
Kicking your right foot and knee toward the ball at the start of the downswing does not mean that you've shifted your bodyweight to the left. It means that you've merely changed your body position. It's critical to avoid transferring your bodyweight to the left foot prematurely before impact. Your bodyweight goes where the clubhead goes and never precedes the club, which requires you to keep your bodyweight on your right side before impact.
In a good golf swing a change of body position creates the swing momentum of the clubhead and encourages the bodyweight to shift to the left after impact.
Equally important is to shift your weight to the inside of your right foot as you go back and to the inside of your left foot again as you start down and hit through. That means you don't have to shift your bodyweight dramatically during the swing. Otherwise, you cannot feel your bodyweight on the inside muscles of your legs and feet during the swing.
Incidentally, for balance and power your center of gravity, a small spot just below your navel, should not be allowed to move excessively during the swing. To keep it constant behind the ball from address through to impact, it's essential to avoid immoderate weight shift.
Too much weight shift leads to superfluous move of your center of gravity, costing you power and balance, plus accuracy. You'd better focus on changing the body positions, which encourages your bodyweight to shift automatically in the proper fashion.
When you toss a somewhat heavy bag to the left with your arms and hands, your head and upper body do not go forward together with your arms and hands. They move backward while your arms and hands go forward. The same theory needs to apply to the golf swing.
Likewise, when you play the ball in tennis, your hand goes forward toward the spot where you want to send the ball but your head and upper body never move forward together with your hand. They move backward for balance and power.
To counter the effect of your legs and hips that move forward, you'd better try to move your head and upper body slightly backward through impact rather than seeking to transfer your bodyweight to the left.
That is, as you should purge your mind of any thought about intentional weight shift to the left or right when you toss a bag or play tennis, so should you do the same when you swing a golf club.
Striving for an intentional weight shift during the swing results in overdoing it, frustrating your efforts to perfect your weight shift.
To attain automatic weight shift you are better turning your attention to your spine. Focus on tilting your spine back through impact just the way you would do when you push something forward as hard as you can. That way you can keep your upper body and head from moving forward toward the target together with your hands.