There are so many different views on how to drive up the sales figures of your ebooks. You have your strategy and I have mine. Ask ten indie authors how they do it and you'll get ten different answers.
Guido Henkel is blogging about ebook distribution at his blog. I have to admit, he has an interesting distribution strategy to drive up his Amazon numbers and thereby his ranking. He advocates only selling through Amazon, Barnes & Nobel and Kobo and not listing with any of the other sellers.
I'm not sure if I agree with him or not. Only time will tell if his strategy will work for him. And ... the operative words here are for him. Read about his strategy at Focussing your distribution and see if you think it might work for you.