Summarize the following:
Because the pedals are always moving on a fixed gear, turning can feel very different than when riding freewheel bike. Don't take corners too tightly or your pedals may end up scraping against the ground or you might topple over. Slow down significantly when going around corners and take them wider than you normally would on a freewheel bike. Purchase bike safety gear at a bike store, department store, or online. A helmet will protect your head if you fall off of the bike. If you are just learning how to ride a bike, you should also consider wearing additional protective gear like knee pads, elbow pads, and a mouthguard.  Make sure that the helmet fits snugly, but is not too tight on your head. Ensure that your bike has reflectors if you plan on riding it when it gets dark out. Many areas require you to have a front light and rear reflector while riding at night. Even if you have experience riding a freewheel bike, riding a fixed gear feels completely different. For that reason, you should practice riding it in an area that's free of obstacles until you're confident enough to ride it in other places.\ If you notice that the bike chain is drooping or loose, it could make it harder to ride the bike and could damage the chain. You can tighten the chain by unscrewing and repositioning the rear wheel further back. Check your bike chain periodically to make sure that it's tight. Professionals at the bike shop will also be able to replace or tighten your chain.

Summary:
Take wider corners when turning. Wear a helmet and safety gear. Practice in an empty area when starting out. Keep the bike chain tight.