Johnny Miller’s “brush-brush” drill is, by his own account, his single best golf tip. Here’s the tip: Use the toe of your club to make a line in the grass, then set up centered over the line. Make a half swing and try to brush the grass on the target side of the line—not a huge divot, just a slight brush—then repeat. I do it twice in a row, because it instills a good rhythm: “brush-brush.” This drill should result in tour-style impact.
The reason this is a dumb tip is because it presumes that practicing a good mechanic on one’s practice swing makes it more likely you’ll use that same swing when you’re over a ball. Golf teacher Fred Shoemaker has filmed probably 10,000 golfers of all abilities and has repeatedly found the opposite to be true. For mid to high-handicap golfers, the presence of the ball radically alters the swing and results in poor mechanics.
So “brush brush” your way around the course. Just don’t expect your score to change.