Depending on the game, league, and whether it is a tournament or casual play, dart rules vary widely. The following are standard rules, and should apply in most dart games, no matter where they occur:
To determine who plays first, each player throws one dart. The player who hits closest to the bullseye decides the throwing order of all players.
If a player drops a dart while preparing to throw, the throw does not count and he can retry. However, if the player's arm is in the beginning of a throwing motion and he drops the dart, then it counts as a throw.
In electronic dart games players stand 8 feet from the board and cannot step over the throwing line. A foot foul is when one player steps over the throwing line.
Never walk across the throwing line during play. It distracts the player throwing.
Always use common sense when throwing darts, and never aim or throw them at another person.