A top spin refers to the top of the volley ball spinning forward. It can be a difficult hit that has a great pay off. The ball dives suddenly in front of the opposing team and looks impressive and is often mistaken for a ball going past the end line.
There are some tips that apply to almost all serves, and they apply to the top spin as well. Always use follow through when hitting, which means when serving don't plan to stop the motion of your arm when making contact. Aim beyond the ball, and hit like the ball is a few feet beyond where it is. Keep your eyes on the ball. Focus on the hit, and try not to let other thoughts distract you.
The actual motion a few techniques that can sometimes take people a few years to learn. A good tip is to practice with a small ball, like a baseball, and flick it against a wall repeatedly.
1) you need to position yourself so that you are under the ball to hit it. Some players throw it behind the back, or use different hands. The thing to remember is to be under the ball as it arcs upwards, so that you can apply the perfect motion to the perfect spot.
2) hit the ball with your hand open, the arm firm but the wrist relaxed. Your arm should be fully extended at the point of contact. Aim for the bottom center of the ball.
3) snap your wrist. Here is why it is good to practice, so you can feel the snap as your hand hits. Your arm should pull forward and down as you hit the volley ball.
4) follow through. This makes all the difference between a great top spin and a lousy serve. The follow through is almost as important as where you hit the ball, and the snap. Make sure to practice and get the arm motion right.
5) have fun with it on your own time. Some experts recommend leaving the left arm up, and bring it down as the right arm comes up to add power. Practice with a volleyball to admire the power from a good top spin. When you learn how to serve a top spin the ball can be hard for the opposing team to return.
When you serve the volley ball with a top spin, the spin will help lift the ball in the direction it's spinning. This is called the magnus effect, whereby the spin causes a lift in the right direction.
Remember anything worth learning can take time. Have fun and try different techniques. What works for one person, like leaning back to far, may not work for you. You may need to toss the ball and step back, to serve a good top spin. The snap of your wrist does no good if your aim is terrible and you don't hit the ball in the center. The lack of a top spin can cause a erratic path to the ball. When you serve the top spin correctly, however, the ball not only has height in flight but dips suddenly, often surprising the other team.