The first, obvious ways are to make sure your listing is complete. It needs the proper photos, descriptions, categories, and so on.
Next, get your book out into the hands of any and all quality reviewers you can. Of course, aim for reviewers in your book's target area. These reviewers will be read and followed by your target audience, and assuming of course you wrote a great book, they will then promote your book to all of those people. The more positive reviews you have on your book's page, the more likely people will be to buy it.
Make sure YOUR profile is very up to date. Have your photo, your description and so on all updates. There is a blog option for authors - take advantage of it, and update it regularly. That way people who are interested in your book know that you're active and interested in feedback.
Why Be on Amazon if it Costs More?
Some visitors say that they might as well sell their book directly on Lulu, CafePress etc. since it's cheaper to do that than on Amazon. They feel that nobody will "seek out" their book on Amazon anyway. They're just going to have a personal website with a link right to Lulu to buy the book.
In the global scale of traffic, pretty much zero people go to a personal website. On the other hand, eighty quadrillion people go to Amazon. I run websites for a living and for example my large website, BellaOnline.com, gets over 20 million pageviews a month. Even my personal website gets 2 million pageviews a month at lisashea.com. As large as those sites might seem, they are *tiny* compared with the traffic Amazon gets. Even if a tiny, tiny fraction of Amazon visitors find and buy your book, it will be many times larger than the volume your own site would see in a year. Never underestimate the power of being listed in a system that immensely large.
You may say that nobody will accidentally stumble on the book in Amazon - but a ton of sales are made that way. Your book is on a topic. Whatever it is, there are thousands of people on Amazon who enjoy that topic. Let's say it is a fiction book on medieval knights. People searching for medieval knights will find your book and a portion will buy it. If you get a few positive reviews from people, you'd be impressed at how many sales you will make. Also if a few people buy your book and also a similar popular book, now your book will show up on the "people also liked" listing for those other popular books. So that gets you a ton more purchases.
There are also the lists of similar books that people put together (that you yourself can put together) that would show up on pages with similar books. Then there are the author blogs which can get very popular. If you talk about topics that your book is related to, then people who are interested in those topics will subscribe and might eventually buy your book. The few extra dollars in cost the visitor pays is nothing at all compared to the huge, huge benefit of being in a system as gigantic as Amazon's. Again if only say .000001% of people buy, that is still a huge number.
On a separate issue, very few people in the world know and trust Lulu. The vast majority know and trust Amazon, and have an account there already. I have done many studies selling the exact same item in two different "stores" (i.e. Amazon and elsewhere). 99% of people will buy through Amazon because they know and trust them. They would deliberately not use the other store for many reasons - they don't trust them, they don't want to make an account in an unknown system, etc. If you want to make a sale, you want to make the process as hitch-free as humanly possible for the potential buyer.
You'd be surprised how many people are willing to pay far more for an ease of use reason. Especially if they get free shipping via Amazon. And have gift certificate credits there ...
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