So, what are you doing right now? You seem to gravitate towards things where you are able to evaluate and make your own decisions, am I right? Can you handle being supervised, or do you have trouble with that? It's really wide open to you. I am older and tend to gravitate towards the "safe" jobs, with the steady stream of income, benefits, etc. But the people who really get ahead tend to do it by taking chances (calculated risks). The ones that immediately come to mind would be in the outdoor travel and tourism industries, including hunting guide, park ranger, game warden. There is still a need for people who can fix their own equipment rather than running off to a repair shop! Or, if you want to start a business, consider engine/motor repair - jet skis, boats, etc, not just lawn mowers! Some of these jobs may be seasonal, so you may need to consider stability as well. Government jobs (parks, etc) tend to be more secure, but, don't always pay as well. People tend to move between jobs an awful lot nowadays, without it being frowned on like it used to be, so you might want to sort of explore for a few years and see where it takes you!
The on-line business idea is something I only dabbled in, so can't help there.