Overhead Serve for Beginner

Question
Can you please tell me exactly how contact is made with the ball in the serve.  I am a strong tennis player, so I have no problems with the stance, toss, high elbow, weight transfer.  Some people say punch with the heel of your hand.  Others say slap with the palm.  Some say keep a stiff hand/wrist, others say flick it on contact.   Is it a throw (you carry it to a certain extent) or is it a bump (you try to indent the ball to give it power)?  No matter what I do, the ball dies in the air before the net.

Answer
Alex,

Ok everyone who gave you advice is right.  Each player is telling you how to serve a different type of serve.  To serve a float you keep your wrist straight and to serve with top spin you snap your wrist on contact.

Here is my best advice to you.

Keep an open hand, make contact in the middle of the ball, with your palm and fingers.  Make contact with the ball just in front of your head with your arm fully extended.
After you are comfortable serving this way, try to serve with top spin (snapping you wrist), then work on a float (stop your swing on contact so there is no ball rotation).  

It is a throw if you carry it to a certain extent, but it depends on the ref when or how they will call it.

How tall are you?  How much do you weigh?  How old are you?  I am asking these questions because I can give you different drills depending on your answers.

Good Luck,
Steve