Art commissions?

First you list your offers and prices, as well as including examples (or links to examples) of your art so people know the quality you're offering
Payment is best done via Paypal, it's safe and secure and can be retracted if something goes wrong
Get paid half at the start of the job as a deposit, and half at the end. Way too many people will commission you, promise to pay once they see the finished art, then scarper once it's done. Don't start their art until you've been paid the first part
To gauge prices, work out how much effort it'll take (like how difficult it'll be), and how much time it'll take. Combine those to work out what you feel is a reasonable price

This link is from 'DeviantArt', Rose...

https://www.deviantart.com/lucky978/journal/A-Beginner-s-Guide-to-Offering-Commissions-Online-468025801

Yes, get educated. An artist I knew would not get all his commissions from the galleries/ museums, but it was pre- internet.