While you might be able to expect initial sales from family and friends who know about it, actual sales from people stumbling upon your book depends on a few factors when you upload it.
1.) Have you chosen the correct keyword phrases and categories?
2.) Are these categories extremely competitive?
3.) Did you incorporate these specific keywords and categories in your title, subtitle, and book blurb?(Note: not everyone can finagle a way into putting the word thriller in their title, but some can do it in their subcategories although at times that may seem too sales pitchy, not that anyone but authors who know what you're doing would notice or even care).
4.) Do you have between one-hundred to three-hundred people ready to buy your book when it is released? (family, friends, subscribers) When you can sell around that many copies the first three days of your release, Amazon's free marketing kicks in. Hot New Releases List, Those Who Bought This Book...etc. That's pretty much awesome sauce if you can manage it.
5.) Does my amazon page look inviting?
6.) Is there too much front matter before the actual sample chapter begins, thus impeding your readers from getting into the book right away?
If the answers to these questions are a big fat no,(or a big fat yes to questions 2 and 6) then uploading your book and walking away from it is going to get you nowhere. You essentially need to take your writer's cap off and get serious about marketing. An indie author doesn't get to be complacent in that respect. Becoming a book marketing guru can be daunting and overwhelming when looking at it as a whole, and figuring out where to start has made many authors give up before giving it a chance.
Which is why I am super happy to be answering this question for you. Not that you asked how to market your book. I suppose I've basically answered your question, but I'd like to take it a step further and give you a place to start so you aren't flailing around in the deep quagmire of marketing do's and don'ts.
Amazon's search engines are designed to find books listed under popular categories and niches so keywords are going to be your best friend. One book that is absolutely stellar at explaining the process behind researching keywords is a book called Making a Killing on Kindle(Without Blogging Facebook Or Twitter) and another book called How to Sell Fiction on Kindle.
The Reader's Digest version is this: go to Amazon.com and start typing in your genre in the search tab. The goal is to take your main genre and find subcategories that are popularly searched on Amazon. So when I type in the word Thriller I get "thrillers in books, mysteries and thrillers new releases 2016", etc. Now type in "thrillers a" and you get "thrillers and suspense books" etc. these top key phrases are the ones that are searched the most by people interested in that genre. Now try typing in "thrillers b" and you get "psychological thrillers books" and other key phrases, but this is an important thing to discover. Many people are searching for psychological thrillers. Does your book fall under that category? Is it a psychological thriller, a serial killer thriller, or possibly some other type of thriller that can be narrowed down to a specific niche?
This can be a long and arduous way to research keywords and phrases, which is why I think grabbing those books that I mentioned above and memorizing the very dickens out of them is a great beginning for your marketing guru journey.
Why? Because most of the research has been done for you, and you get a list of the most highly ranked keyword phrases for your specific genre...all current. You are also given instructions on simple html coding to help make your amazon page sparkle.
I hope this information is helpful for you, and good luck with your book. I hope you are able to get it uploaded and visible on kindle as soon as possible. If you’re interested in learning more about the best practices on marketing your books feel free to visit me on my website at The Blond Guerrilla: Guerrilla Marketing, Writing, and Self-Publishing Your Book. http://theblondguerrilla.com Or set up a call and we can work on a plan to help you sell your books. I’m always excited to help fellow authors in their quest to get their books discovered.
Happy marketing my author friend!