Kopking, you are correct. When you serve, the most important factor - besides timing - is your wrist movement. You have to hit the ball high and hard.
Samwise, you have my recommendation(s)

Tennis is a very fun and rewarding sport once you get the hang of it. Took me a year, but then again, I\'m not *that* talented
Bozco, how long have you hobbied the sport? Do you prefer doubles or singles ( tournament-wise )?