While I used to see "art sales" simply as bonus money coming in on the side, over the past few years it's become enough of an asset that it justifies an art dealer, record keeping, insurance, and taxes at the end of each year. It's currently 25% of my total income, and that has a lot of impact over my work. And just like storytelling, design and page flow--abstract principles that keep my career afloat daily--art sales also deserve to be studied, theorized, and understood.
These are guidelines, not rules. And while most of them usually work for me, they might not all work for you, so keep in mind that my market might be different than yours. Because not only do we not draw the same, we probably have different sorts of buyers.
1. Don't stay on a book for too long
I find that doing mini series of 4-12 issues is optimal for selling art. If you spend a year doing one-shots or 2-3 issue minis, you'll be hard for buyers to keep track of because it's too infrequent. And it's hard to make an i