With 1 Teammate:

Put one foot next to your teammates' foot.

Put your other foot next to the out of bounds line or half court line, your teammate should do the same. Be careful not to put your foot on the out of bounds because if the ball touches you, it will be out on you.

Make sure you're both wide and your feet are planted, not allowing the offensive player to get anywhere or pivot to anywhere.

Put both arms and hands straight up in the air, your teammate should do the same. Some coaches say to pretend you are like a tree with big branches going straight up. Do not reach in, you can get called for a foul. By putting your hands up in the air, you force the offensive player to attempt a bad lob pass over your hands. Often, you will be able to intercept the pass just by having your hands up.

During a trap, when the player you are trapping has picked up her dribble, you should yell, "Dead! Dead! Dead!" repeatedly until she makes a move. This tells your teammates that the offensive player cannot dribble any more and that they should deny the pass. 

The same as above, but the second teammate plays off, the trap, between the trap and where the offensive player would want the ball to go. For example, if the trap is on the sideline at half-court, your 2nd teammate would be somewhere in the front court, between the trap and the next closest player. If the trap was in the corner, she could either be between the trap and the basket or near the foul line extended, depending on where the offensive player's next teammate is. The third teammate tries to intercept the pass that the trapped player might attempt. If the pass does end up in the hands of one of the two girls who are trapping, the second teammate can take off for a fast break. One of the two girls trapping can throw it long for her.

Whenever there are two people on someone, it means someone on the other team is left wide open. The other 3 players on the team should deny the pass when the trap occurs. The player denying the pass on someone closest to the basket should also guard the paint in case of any cuts. The player who should be left open should be the one farthest from the ball. Good communication will prevent a pass to the open player.

When an offensive player has the ball and picks up her dribble, you should D-up against that player and yell, "Dead! Dead! Dead!" for your teammates to deny the pass. The offensive player will want to pivot on one foot to try and make a good pass. You want to straddle the leg that is not the pivot leg so that she is unable to move it. Keep your back, arms, and hands straight up in the air so that you do not foul. Do not fall into the player, you cannot make contact with the player's body. At other times, it is better to straddle the front foot, regardless of whether or not it is the foot the player can move or not because if the pivot is in the font, facing the basket, you do not want to run to the back of the player to straddle the foot that can move. It would leave the basket wide open as well as open many passing opportunities for the player. For example, sometimes, when players are bringing the ball across half-court, they pick up their dribble when they are rushed at by the defense, especially when it is someone who is uncomfortable handling the ball. Rush at the offensive player to try and force her to pick up her dribble, then straddle the foot that is put forward.