Create an online store if appropriate. If you are an arts and crafts blogger, create a shop through etsy or another service for selling your artwork. If you are a writer or illustrator, search for a website that will sell T-shirts with your slogans or drawings on them. Many blog topics are not easily tied to products. You don't need to sell anything to make money, but if it fits your blog, do it.
Hi Sam! I love your site. We should definitely connect. I’m a school counselor and recently launched a site for parents to address pertinent teen topics. Like you, I struggle with the ultimate service I’d eventually offer on my site, but Ramsay’s idea is a great start. He’s absolutely right that people are looking for fresh content for their sites! Best of luck to you and I hope we can collaborate.