I work for a company that makes a link management plugin, and we think about affiliate links all day.
In my experience, every post is monetizable with affiliate links.
I would go through your existing content, and try to see where you can recommend products. If you have a lot of info content, ask what problem brought a user to that page, and recommend a product to fix their problem.
Of course, if you don’t have significant traffic you won’t make much money at first, but I know a lot of people who have built hug businesses with affiliate marketing