'Pull' Drill - Focus will be on learning to 'catch' the water with your forearm and pull yourself through the water. If you feel your lats (the muscles under your arm pits that go down the side of your back) engage, then you are starting to get it. If your shoulders are tired, then you are still using too much shoulder and not enough lats.
Pull Buoy - A swim aid that you put between your legs to help you maintain a neutral body position while concentrating on your pull rather than trying to remember everything at once.
Single Arm Drill - Push off the wall with both arms extended in front of you with your hands touching, one on top of the other. Rotate to your side so that you are lying on your left side with your left arm in front on you. Now, swim down the pool, using only your right arm - once you get to the other end, try the same thing, this time lying on your right side and swimming with your left arm only. Keep a strong kick going and focus on the pull portion of the stroke.
Closed Fist Drill - You will be swimming freestyle with your hands closed in a fist. This should get you to have a better 'feel' for the water. Unless noted otherwise, this is usually done by swimming with your hands closed in a fist for 4 strokes, and then open your hands for 4 strokes, alternating until you get to the other end.