Golf is actually about hitting the ball from the teeing ground into the hole in as few shots as possible. And there is no requirement, as Bobby Jones wrote, to look pretty while doing so. And what did Bobby Jones say we should focus on after deciding the shot we want to hit? Hitting the ball. Simple enough, one would think. But it actually isn't.
The other day I was playing a round at Dunes West near Charleston. The putts were dropping and so despite missing a few shots I was still one under at the turn. On the tenth tee I stood over my tee shot and, suddenly, as I took the club back I thought about making a fuller shoulder turn. The ensuing weak slice left me way back and nearly in the trees. Only making another long putt allowed me to save par. It can happen that fast. Right in the middle of your swing thoughts have a way of intruding.
Most golfers have swing thoughts--things they think about and make certain of doing either before or during the playing of the shot. Bobby Jones tried to have no more than one at any given time. Jack Nicklaus played well with as many as five. But any swing thoughts are best considered before the shot, not during it. When you take the club back your sole focus should be on striking the ball in the required manner to produce the shot you're looking for.
If swing thoughts are intruding during your swing, I have found that talking to yourself helps. As you are swinging you might say to yourself, "Hit the ball." Saying it to match the cadence of your swing helps; as does trying to say the last word as you strike the ball. Talking to yourself as you swing isn't a sign of insanity and will really help keep other distracting thoughts from intruding as you swing. Try it. You might like it.