Fortnite's slide mechanic can be a great way to get around the map quickly and surprise your opponents. However, you can also use it to damage them! Here's how:
When you're sliding down a hill or ramp, jump just before you reach the bottom. This will cause you to launch into the air and come crashing down on top of your opponent, dealing damage.
You can also use this technique to destroy enemy structures. Simply target the structure with your pickaxe while in mid-air and you'll deal a hefty amount of damage.