To start off with a very simple swing thought, I suggest:

When you reach the top of your backswing, start the transition by turning your hips back towards the left and pull your right elbow close to your right hip while trying to keep your back and right shoulder facing the target until your arms are well into the downswing.

Remember your shoulders don't have to move far from address to the top to address and then to the finish. In all, they move maybe 2 ft.

This will stop your right shoulder from lifting and coming over the top.

Try that ... if it doesn't really cure the problem, post again and we can go to more complex stuff and drills but try the simple cures first.

__________________
Golf is easy ... once you know how.
Graham Arnott, teaching professional
Kelrosa Golf Studios
www.kelrosagolf.com
Class 'A' PGA Member
Full Member: World Golf Teachers Federation (GB&I)