Officials.
There is a referee who controls the game and inflicts the penalties.
There are two umpires, one at each end, to decide whether a goal has been made. There are two timekeepers to keep the time of the game and a penalty timekeeper who keeps the time of players ruled out and notifies the player when she may return to the game.
There is for each team a captain, who makes the decisions for her team, and she is responsible for the good sportsmanship of her team.
There are many little tricks in ice hockey that may be acquired with practice, but the object of the game should be to have as clean and fast a game as possible, where skillful playing holds greater sway than roughness.