Get your weight to the inside of your right foot. Let it 'flow' back with the clubhead, and 'flow' through to your left side.
Step through drills help get this feel (or just swing back, lift left, swing 'through' lift right). You are the center of a 'swinging' on plane force.
Always balanced.
The swing is a lot simpler than most make it - the less you 'do' the better.
Thinking only of getting the weight back and through and doing nothing 'with' the hands/arms can help a lot of people. Let the hands and arms go where they go. They 'support' more than the 'do' during a swing.
People like to think they can 'add' force, when really they can only 'support' and 'build' speed, not 'make' speed happen. Understand the physics of a rock on a string.
The better you get, the more you appreciate the shoulders, so if you must focus on anything, just thinking of the plane and turn of the shoulders, and letting your body 'flow' and 'react' is a good thing.
Hit the ball with the back of your left shouder.