Write down every topic that you are knowledgeable or passionate about. You'll have a much easier time making money from a blog you are interested in, rather than trying to write content you don't like because you think it will make money. Some examples are hobbies that you enjoy, your career, or some specific and miscellaneous knowledge that you have.
For example, Erica Tannen, a former retail executive and founder of The-e-list.com, describes her site as “an excruciatingly opinionated guide to the Connecticut shoreline and best Connecticut shopping.” The hyper-local blog, which now has over 16,000 free e-newsletter subscribers (the money comes from ad revenues) and 74,000 monthly page views, includes reviews of restaurants, shops and tourist attractions, as well as notifications about sales and events.
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.