Arnie's 10 Rules of Golf Etiquette from Golf Digest
 

Easy to follow these to make your round and others' better. I especially liked the one on raking the bunkers. When watching the pros play, you see them hit their bunker shot and climb out and clean their spikes. What you don't see is the meticulous way the caddies smooth the sand, filling in the divot and stance holes, but also smoothing out the impact mark in the sand as well as the footprints from waking in and out. They are graded on this. Too many times I encounter a bunker that looks as if carpet bombing has occurred.

Arnold Palmer: 10 Rules For Good Golf Etiquette : Golf Digest