Don’t skimp on your author bio and author photo, as well as on your book cover. So, if your photo file is tiny (20 – 100 kB) then it ‘s probably not good enough resolution. If you get a professional photo, maybe even holding your book, it reflects well on your professionalism. (Support local photographers).
Remember, readers don’t care much about why you chose your genre… they more want to know that you’re an authentic writer. Particularly with non-fiction, life experience counts and your story and motivation should be apparent in your author bio.
Promocave also offer a custom researched book promotional package, including proven search-engine optimisation and Amazon optimisation techniques.
For free, authors can set up a LinkedIn Company Page (as Jorge suggests), Facebook Page (just for the Book), and use the Author Marketing App installed inside a Facebook Page to help people bounce from the page right to the Amazon book buy page.
I hope you get infinitely more book sales with this independent book promotion site review.