Yeah, that's what I'm saying... and I'm sticking to it! What I think sells books are 1) good reviews (like starred reviews and getting in big newspapers like the NYT, etc) 2) awards--this is a big one! Once you get on a state list, schools all over the state will buy your book! 3) school visits--you can reach a lot of kids within a short amount of time.
When you do a store signing, even a successful one, in my opinion, won't do much. So what if 40 people bought your book? Let's be honest--at least half of those sales were sales purchased by your friends! And if you're are a prolific author, you can't expect your friends to go to all of your signings and eventually you will find yourself at least once twiddling your fingers, sitting alone, in complete embarrassment! There's no worse feeling. And if you do a lot of bookstore signings this can happen more than once! Of course this is the bookstore's fault because they didn't advertise and let you do a signing when they don't have a built in story time audience, but what do they care for? They're not losing anything by having you sit there!
So my advice to all of you out there is just don't bother doing them. Group signings may work better... but even still, it's a drop in the bucket. If you have deadlines and are stressed out it's just not worth it! Save your energy for something else!