How do I promote my book with keywords on Amazon?

You can do use keywords in your book descriptions, but be sure to do it in such a way that it reads naturally and never forget that a human is making a buying decision based on what you write, so if you keyword stuff your description you may get a marginally better search ranking but will definitely get a drop off in purchases and conversions. You also run the risk of Amazon deciding they don’t like your description and potentially removing your book from their marketplace.

Write for your customer first, the search engines second, and as the technology for the search engines improves over time your book will naturally rise to the top as long as you offer a quality product that people are willing to purchase and leave good reviews for.