Amazon doesn't pull the cover back on too many things, but their suggested keywords from the search bar are where I find most of my keywords.

My process is quite simple:
1. Go to an incognito (or private) window on your browser.
2. Go to Amazon
3. Once you are at the search bar, simply put in your seed word. Your seed keyword is the broad niche that you are going to be targeting. Four our example, let's use pink notebook.
4. In the search bar, type in pink notebook, then put a space. Make a note of the keywords that you might be able to make a journal/notebook/diary around.
5. After you have noted down all the words from that group, backspace and put each letter of the alphabet after pink notebook. For instance, pink notebook (space) a, pink notebook (space) b, etc. Give it a try. You'll be shocked at the ideas that you can come up with.

Don't let keywords get ya down!