UT has a lax team thats pretty decent (club). Fun sport. Just "hit the wall" aka throw the ball against a concret wall for an hour per day using both hands. Then practice picking up "ground balls". Keep both hands on the stick and get your elbows as close to the ground as you can, scoop up the ball and explode forward with the stick close to your chest to protect the ball, and then get rid of it (pass to someone open and fresh to get a fast break going)
If you can throw and catch with both hands and be a ground ball machine, you can get playing time. Having stamina helps too.
Playing D is similar to playing linebacker. Got to keep on the balls of your toes, keep your feet chopping, watch the players hips, NOT the stick/ball, dont cross your feet or turn your back on the player with the ball. Keep your center of mass low, meaning get your feet sholders apart, and butt low. That way if the guy your defending gets into your body, you can control him easier. Keep your head on a swivel between the guy with the ball and the person you are covering (making sure he isnt trying to back door cut you, kind of like in basketball) Keep your stick head out in front of you, splitting the field in half, it does no good at your side. Poke check, poke check, poke check, Learn it, master it, I cant say it enough. Open your mouth and talk when playing. "I got Ball" "I got your left/right" "Ball Down" "Pass" "SHOT". Take advantage of the persons weakness, make them use their hand that they are not comfortable with (usually left)
ESPN during the Spring usually has some good D1 college ball on the weekends that you can watch. I would also recommend checking out youtube for instructional, coaching videos.