When you hit your ball into an area where you might have difficulty finding it or if it's likely out-of-bounds, rule 27-2 allows you to hit a provisional ball before leaving the tee. You must declare you are playing a provisional before making the shot.
If the original ball is found and played, you will incur no penalty. The provisional ball becomes the ball in play when the original is declared lost.
By hitting a provisional ball, you will save time for yourself, your group and the groups behind you.
From the time you begin looking for a ball that may be lost, you have five minutes to find it (rule 27-1c). Anyone can help you look for the ball, even people not in your group. After five minutes, a player must play a ball under penalty of one stroke. Failure to do so will result in a penalty of two strokes in medal play or the loss of the hole in match play.
Wave The Group Through
If you determine that a hole or more is separating your group from the one ahead of you, Section I - Etiquette reads that you should allow the group playing behind you to play through as a courtesy.
"On The Clock"
In addition to the rules that cover certain pace-of-play aspects, the administration of professional and amateur golf tournaments can deal with slow play by placing competitors "on the clock." This happens if a golfer is guilty of slow play that results in their group being "out of position," which is often defined as being at least one hole behind the group in front but can be based on criteria set by the tournament's ruling body.
A golfer "on the clock" has his pace of play monitored. Golfers "on the clock" who do not speed up their play can be assessed a two-stroke penalty.