Reading as extensively as you can within your area of interest is always an excellent start, both for generating ideas and testing the ones you have. Sooner or later, though, you have to get around to actually writing if writing is what you want to do.
Many writers find that blogging and/or making regular posts on social media can provide an outlet for the desire to write about a particular topic; for those with interests in fiction, developing a fan wiki or writing fan fiction may be just what's needed. The key to making it work for you is discipline---both the discipline to write and post regularly, and the discipline to write those posts as well as possible. Learning to write well takes writing a lot, and there is no escape from this requirement. Likewise, you have to go through the slog of writing when you'd really rather not before you can learn the art of staying focused on your passion or interest even when the writing isn't coming easily and the metrics suggest that you're not generating much interest from whatever audience is there.
For those interested in testing the waters of whether an idea has book potential or pursuing the idea of blogging, I'm posting a link here to an article by Trevin Wax on building a blog and a platform for your writing: Is There a Book in You? (thegospelcoalition.org). As a Christian author, Wax writes primarily for a faith-based audience, but his advice on how to lay a solid foundation for both blogging and exploring whether your idea has book potential is sound for writers looking to explore almost any topic.