Here's the deal: Know how to swim well before stepping on the board. Always dive with someone else. And… Protect your noggin! You've gotta know the water depth before you dive, and never ever dive into shallow water. Check around for signs or ask a lifeguard. Diving areas are usually marked. In case you haven't figured this out yet, above-ground pools are not designed for diving. They're way too shallow! (Lots of in-ground pools aren't deep enough either, so check out the water before you dive.)
When you are on the board, enter the water straight on and make sure there's nothing in your way before you leap. If people come into the diving area from other parts of the pool, wait until they're gone, or just ask the lifeguard to clear the area for you. If you jump when there is someone else in the diving area, or even just mess around while diving, you could land on top of someone and get hurt!
Don't run up to a dive. Always stand at the edge of the board or pool and then dive. And dive straight ahead — not off to the side.
It's also important to warm-up and stretch before diving, and then cool down after your plunge session.
Most of all, only try dives that are in your comfort zone. Leave those fancy or stunt leaps to experienced divers. An adult can help you decide which dives are safe to try.