The first spin serve to develop is the slice serve or 'slider'.
It happens when the racquet face brushes around the side of the ball.
The resulting spin takes the ball out wide which often means the receiver has to run right out of court to return the ball.
It is all down to where you put the ball in your throw up.
To hit a slice serve the ball needs to be in front of you.
If you place it a little more to the right (to the left for left-handers) can also help generate more spin.
As you accelerate to hit the ball, slide the racquet face around the outside of the ball.
You should hear a different sound as the strings brush across the ball imparting the spin.
Try to stay relaxed as you hit the ball. Try to feather the ball and glide the serve rather than bite into it.
This will help you get more swing and angle.