Tips for Making Money (for Teenagers)

• Don't lend people money unless they are trustworthy and you know they will pay you back. The fact that someone is your friend does not automatically make them trustworthy or reliable - sometimes, lending money to friends can be like gambling.
  
• Try making flyers on your computer and hanging them on telephone poles. Some places will allow you to hang ads on a board of some kind. This can be very helpful. Be sure to add in your flyer how much you charge for each service; that way your customers know what to expect, and there aren't any surprises when it's time for you to be paid.
  
• If you are able to make a product, sell the product for about 10-20% more than price of production.
  
• Work for more than money; work to learn. Even flipping burgers presents opportunities; watch who they pick for management, how the workers are organized, anything. Rich people own businesses, they don't work for them. Money is temporary, knowledge is permanent.
  
• Try to dress sensibly. This will help you look responsible and dedicated.
  
• Organize your thoughts and keep a simple plan for making money. Trying to tackle too much can be very stressing and can be a hazard to your developing body.
  
• Sometimes you can get work at a summer camp. This is useful because it's rewarding and doen't interfere with school at all (unless you have a year-round school, of course).

source: wikiHow