Jane at Writers Digest writes about the purpose in starting a blog before you have a book or your own writing of another kind, to promote.
What do you put on your site or blog when you have no book?
Here’s a starter list of ideas. Keep in mind you don’t have to blog. A site can work as a business card until you have a need or an idea to add more content/interactivity.
- Do not write about the writing & publishing process, unless you have some very unique insights, or a very unusual spin/voice.
- Unless you are the most boring person on earth, you have passions and interests that aren’t tied to writing & publishing. These things might be witnessed in your written work (maybe you have a fascination with a historical period), or they might be complementary life pursuits to your writing (e.g., librarian or teacher). What perspective or insight can you offer related to these things?
- What do you know about, intimately, that no one else does (that you can still write about!)?
- What do people compliment you on constantly?
- What types of media/materials/books are you always reading? Are there observations you can share? Snippets from your consumption?
- Would it be appropriate to review books?
- How about interviewing people who interest you?
- Is there content/media you can curate?
Writers are usually curious and observant people by nature. Use that to guide you.
I think the best plan for a writer to keep a blog is to write about something they love, a favourite hobby for instance. This way you can keep your focus on your passions, write about something you are knowledgeable about and, as a bonus, attract others who share your interests. You might even find new ideas and events which you would not have found on your own but can get from the contacts you make.