Go to fiverr dot com. Check out the most popular services offered.
Match your skills/experience against this list.
Either start out listing gigs at fiverr or move directly to setting up your own site with WordPress (dot org not dot com) that sells your services at a higher price. If you set up your own site, start with accepting payment by PayPal. You can get your own CC merchant account later.
Remember that the market determines what you sell more than personal interests. For example, if you like writing poetry in 17th Century French, there’s probably not enough customers out there to make it worth your time.
So true, where are the Medici’s of today when you need a billionaire benefactor?