I've included links to some pertinent articles. 

1. Learn to serve with lots of spin by accelerating the racket through the ball and grazing it.
   (Here's the article Serving Short with Spin. Here's another, Five Steps to a Great Spin Serve.)
2. Learn to serve various spins, including backspin, side-backspin, sidespin, side-topspin, and topspin, and be able to serve with sidespin in either direction.
   (Here's the article Importance of Serve Variety.)
3. Learn to serve low.
   (Here's the article Serving Low.)
4. Learn to control the depth and direction of the serve.
   (Here's the article Depth Control of Serves.)
5. Learn to serve with spin using a semi-circular motion so you can create different spins with the same motion by varying where in the motion you contact the ball. 
   (Here's the article Semi-Circular Motion on Serves.)
6. Learn to minimize and do quickly this semi-circular motion so receiver has trouble picking up contact.
   (See same article linked in #5.) 
7. Learn to change the direction of your follow-through with your racket the split second after contact to mislead the receiver.
   (Here's the article Exaggerate the Opposite Motion on Serves.)
8. Learn to fake spin and serve no-spin by contacting the ball near the handle.
   (Here's the article Those Dizzying No-Spin Serves.)
9. Learn to serve fast & deep as a variation to your spin serves.
   (Here's the article Fifteen Important Deep Serves. Here's another, Turn Opponents into Puppets with Long Serves. Here's How to Ace an Opponent.)
10. Learn to follow up your serves.
    (Here's the article The Purpose of the Serve.)