When rappelling on a single rope, you always have a choice as to which side of the rope to pull. While on many routes it doesn’t matter, on some raps it may be the difference between having a stuck rope and/or a very difficult pull. Look carefully at every rappel you do, and try and identify potential problem points before pull the rope.
Generally, try to pull the rope AWAY from any obstacles it may hang up on. For example, say you’re about to pull the rope, and you look up and notice a tree or potential rope eating crack below and slightly to the right of the rap station. Pulling on the left strand of the rope will cause the rope to fall to the left, hopefully away from the potential hang-up point.
If you’re on the ground when you pull the rope, you might also get a better angle of pull if you walk off to the side, away from the possible snag point.
Giving the rope an extra little flip or sharp tug just after (not before) it slides through the anchors can cause it to fall farther away from the rock, further avoiding snags.
If you’re rapping in terrain where rope snag potential seem to be everywhere, you're probably better off doing a series of shorter raps using a partial length of the rope.
If you are using partial rope rappels, you can do this Crafty Rope Trick (CRT): If you have plenty of rope at the new stance, pull down as much rope as you can before the final person goes on rappel. This reduces the chances for a hangup or rockfall when the rope is finally pulled from the upper anchor, because there’s less falling rope that can potentially hang up on something.