Make sure first that there is actually air in your tires…it's important, trust us. If you're riding on a hard-packed trail, then put the recommended air pressure in the tires. If you're riding on sand or in mud, feel free to let some of the air out and run your tires a little flat. That way they'll have a bigger footprint on the ground, giving you more traction. Oh, and always have a flat repair kit with you. Always. Seriously, don't leave home without it.