Might I suggest three things:

1. Make sure that full publisher data is supplied and accurate, as you can add a "teaser" to your listing that way. Amazon *usually* allows authors to help with this, at least they have for me.

2. Persuade at least one person to review each book in detail and rate it, as they can (if talented) do the same thing, which can vastly increase the likelihood of people buying the books.

3. Encourage people who've read the book to contribute at least a short comment and a rating, for the same reason.

Reviews and ratings *really* matter for Amazon sales, and their lack may imply (unfairly) that the book isn't worth reading.

You might also seek out Listmania providers who recommend books similar to yours, for the same reason. One can't have too many drivers for sales.

Puddin'
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P.S. You might think about a Kindle edition as well, if your contract with your publisher(s) allows this. Thus far, Amazon is eating the difference between the discounted prices they charge and the list price basis of their royalty payment, although your mileage may vary. I suspect that many people would like "invisible" editions of some books, but it's just a suspicion.