When I notice these slow periods, I go into a feeding frenzy, feeding on any helpful article or tip I can find on the subject.
On Etsy's pages, for instance, there are tons of helpful hints and tips in their shop-owner Forums. I usually start there when I need a pick-me-up.
I have found since I began my shop that I am very fortunate in that I have never had a brick-and-mortar shop. If I had a "real" physical store, in a room, on a street, and if I were to hit a few days in row with absolutely no customers coming in, I would be a wreck.
If I were to hit a few days with folks coming in and just browsing and not buying, I would be a wreck.
Obviously, that is not my style.
Online, however, I can deal with it and even try to correct some things along the way. If I pick up any new tips over the coming days, I'll share them with you for sure.