Sometimes, the answer to a swing problem lies between a complicated mechanical fix and the uber-simple “see ball, hit ball” approach. A vivid image or swing thought often does the trick.
Jack Nicklaus relied on just such a key to prevent hitting the ball left, via hook or pull, in the heat of battle. He merely tried to keep the palm of his left hand facing up through impact. Of course, this didn’t literally happen; the force of the swing and the natural rotation of the arms make that nearly impossible at Nicklaus’ swing speed. Rather, the mental cue helped him keep his right hand from dominating and rolling too quickly over the left, which causes a hook.
If you have a habit of missing left (or right, if you’re a lefty), give Nicklaus’ left-palm-up tip a try. You may just save yourself the headache of making a major swing change.