When I was 12 I was very mature and helped with little kids a lot. I once looked in paper and called people to ask about baby sitting. No one wanted a 12 year old and a couple laughed at me and hung up.

I suggest waiting until you're at least 14.

To list all the ways to make money online would be very tedious. Google is your best answer but it's very tainted with ads and none-sense. Here's some things that actually work.

• Customer service
  
• Telecommunication
  
• Article writing 
  
• Affiliate marketing
  
• Product selling