How to do a Swan Dive?
Distance yourself. One step should do it. You need enough room to build up enough momentum, but if you run then you will probably slip.
Check the depth of the pool. Only swan-dive in the deepest end reachable, as the swan-dive will take you very deep very quickly.
Put your strongest leg forward. Your toes should be just hanging over the edge of the pool. Your other leg can be next to it or several inches behind, it depends on your preferences.
Spread your arms to your side. This is essential for later.
Push off from the side of the pool. Be sure to push slightly up, too. Snap your legs together tightly and lean forward when you do. Your body should be slightly bent.
Force your arms forward so your body is in a pencil-like shape. Do this quickly, as time is tight.
Angle your body at a 45+ degree angle to the water. If possible, do this as you push off from the edge.
As you enter the water, lean your head forward and lift your legs up. You should enter the water smoothly with little splashing.
Practice. This is essential, as nobody can perfectly execute a swan-dive first-time.