One of the best ways to keep yourself in the game and to help your team is to back up on every play when the ball is not hit to you. By backing up you can keep a runner or runners from advancing on an errant throw.
Position - Right Field
Situation: Runner on First, batter bunts the ball, ball is fielded and an errant throw is made to first. If you are backing up first on the play, you may be able to keep the runner from going to third and you most likely will keep the batter on first.
Position - Center Field
Situation: Runner on First, ball is hit back to the pitcher, Ball is fielded and an errant throw is made to second. If you don't move, the runner will easily make it to third. If you are backing, the runner will most likely have to stay at second.
Position - Left Field
Situation: Runner on first, double play ball hit to the first baseman, first baseman overthrows the shortstop. If you are backing up second you will probably keep the lead runner from advancing to third base. If not, it's an easy extra base and maybe a run.
Situation: Runner on second, batter bunts the ball, ball is fielded by the pitcher who makes an errant throw trying to get the runner going to third. If you are backing up the play, you may keep the runner from advancing, saving a run, and the batter from going to second.
As the above examples illustrate, backing up can prevent a bad situation from getting worse...