Wearing a helmet is not required by law, but it is a good idea. If you're involved in an accident while riding your bike a helmet will help to protect you from serious injury. If you are making a left turn, extend your left arm straight out. When making a right turn, extend your left arm and bend it at the elbow so your hand is straight up. If you are going to slow down or stop, extend your left arm bent at the elbow with your hand straight down.
Bicycles follow the one person-one seat rule.
If you have one seat on your bike, there should only be one person on it at a time. According to state law, you must have at least one hand on the handle bar at all times. You can't carry any objects with you on your bike that require both hands to hold on to. Yes, but you must have a light and reflectors on your bike if you do. You should also wear bright colored clothing so that drivers of cars can see you more easily.