Front crawl catch and pull technique?

First, keep your fingers together, and cup your hand. Think of it this way, if you tried to scoop water with a fork, you wouldn't get much, but if you scooped water with a spoon, you would catch much more. Then when you catch and pull, keep your wrist straight, bending at the elbow and pulling from your forearm down to your fingers. You can bend slightly if it is uncomfortable when your hand first enters and exits the water and when your arm is out of the water, but when you pull, keep it straight.