Drafting

This technique is also known as slipstreaming. If you race right behind an opponent on either straightways or in curves, speed lines will appear around your kart. If you keep this position for a few seconds, a slipstream effect will give you a speed boost and allow you to even overtake the person you're drafting behind.

Beware, though: drafting requires that you get fairly close to your opponent. Avoid this technique if the racer ahead of you is carrying/dragging an item such as a banana peel or is surrounded by turtle shells. This could lead to a crash and a loss of valuable time.