As stated in other comments, follow the best business practices. Be kind and considerate, artists are human beings too. Pay through Goods and Services when possible. NEVER write the artist a note containing adult keywords like stating it's NSFW commission; you will get the artist's PP acc suspended.

Now there will be times where legitimate artists do approach you asking for your business. Usually they're just trying to make a living. Always ask for their socials and portfolio; legitimate artists will have them and are continually building their portfolio

If you notice someone claiming someone else's art as their own, you can do the original artist a big favor by notifying them that their art is being used for malicious purposes.

Scammers will sometimes use someone else's art and claim it as their own. Take the time to do a reverse image search through google reverse image search and tools like SauceNAO; you can use Fluffle and FuzzySearch if you're in the furry community