Other writers wait until they have actually bothered to publish something to get fan art. I do not have that sort of patience, so I commissioned Mikhail Shadeed to draw for me, and by "commissioned" I mean "asked nicely, in exchange for saying complimentary things, probably."
My end of the bargain is easy to live up to, since this is basically exactly how I imagine my protagonist witch, Lucy Bakir. She's not fussed with wardrobe, apart from wearing a shawl (it's enchanted); she has a little black housecat named Hecate; and she has a broom, but only for special occasions. Mikhail nailed it with Lucy's posture and expression. She is giving the viewer the equivalent of a shrug.
Mikhail, who works with my nom de real life at the library, is shy about sharing his work. This is dumb, since obviously he's a talented artist, but it would be impolite of me to say so.
Now I just have to convince him and/or other skilled illustrators to conceptualize the rest of my characters for absolutely no money at all even though I have not in point of fact published my book.