Oh, I happen to be an expert on this. It's honestly really fucking easy.
You draw some art, it doesn't even have to be good, make sure to put a recognizable signature to it so people can google you, have a blog or something where the rest of your gallery is, link it to your paypal account or bitcoin wallet or something for people to send donations to.
Again, your art doesn't even have to be masterpieces, but what's important is a certain meme-value that compels someone to save it to their hard drive and later repost it somewhere else. Initially, you will be the one posting your own art in various different high-traffic places until it catches on and becomes viral and your fans are doing your work for you.
Use reverse image search to see who's reposting your shit and where.