When you stand over the bike, you should have 1 to 2 inches of clearance between you and the bar (5 inches for a mountain bike). Your leg should have a slight bend when fully extended on the pedal.
Wear appropriate closed-toe footwear (consider investing in cycling shoes). Avoid loose clothing that can be caught in bicycle parts.
Particularly at dawn and dusk, wear neon colors and reflective clothing. Put reflective tape on your helmet and bike. Be sure your bike has reflectors or flashing lights on the front and back.
Always ride with traffic in the designated bike lane or as far right as possible. Don’t ride too close to parked cars—a passenger may suddenly open the door. Obey traffic lights, signs, and speed limits.
Be considerate of other motorists and pedestrians, who have the right of way.
Toes that aren’t straight-facing on the pedals can cause leg pain. Gripping too tightly can strain your hands, wrists, and shoulders.
Avoid busy streets and riding on sidewalks (in some areas it’s prohibited), where you’re more likely to crash into a pedestrian. Keep an eye out for potholes and other obstacles.
Check to make sure your tires have enough air, look for wear on your brake pads, and keep the chain free of gunk.