If you aren't charging enough that after materials you have enough left to cover your living costs for 3x the hours you spent working on the art, you either lost money, or you'll need to work more than 8 hours/day.
Downtime while thinking about the art counts as spending time working on it.
The problem with this, of course, is that if you sell nothing because the price is too high, you *also* lose money.
By my own metrics, even on some of my highest paid work (composing, crowdfunded mostly via #Patreon at http://www.patreon.com/artsyhonker ) I am losing money. And I'm doing better than a lot of composers I know!
I don't have any easy answers, here.
Mastodon.ART — Follow friends and discover new ones. Publish anything you want & not just art of all types: links, pictures, text, video. All on a platform that is community-owned and ad-free. Moderators: @Curator @ChrisTalleras @EmergencyBattle @ScribbleAddict @Adamk678