How do I choose categories and keywords so my book actually gets found on Amazon?

Think of it as two different jobs. Categories decide which bestseller lists you can appear on; keywords decide which searches you show up for. For categories, pick the most specific, least bloated subcategories that genuinely fit — a smaller category where you can realistically rank in the top 20 gets you an "Amazon Best Seller" flag and real visibility, whereas a giant one buries you. You can also email KDP support to be added to more niche categories than the picker shows. For the seven keyword fields, don't waste them on single obvious words like "fantasy" — use whole phrases a reader would actually type ("slow burn enemies to lovers fantasy", "cozy mystery small town bakery"). Fill all seven, avoid repeating words already in your title/subtitle (they're already indexed), and skip anything you can't honestly deliver. Then check after a few weeks: search your phrases, see where you land, and swap out the ones doing nothing.