Fix computer problems for your parents' friends, or your friends' parents
Web pages, graphics, music writing, animation, copy-writing etc... Get your parents to handle the money side of it, you just do the work (for now). What you don't know right now, you can just pick up on-the-job. (Adults often do this, and they sometimes pretend they knew it all already, so they can look more valuable.) Get started on it now, before the adults discover they could have done it themselves
Work for your parents. Ask them what jobs they would rather not do and would pay you to do. Haggle for more cash than their first offer. They'll probably be surprised (and maybe even happy, but they won't let you know that). This work you do is *on top of* chores, by the way! You already get paid for the chores by being allowed to live at home, eat for free etc.