Something that seems to make people shy away from blogging is that they "don't know what to write about" like a successful blog can only be run by someone who has a really interesting life. Not true.
A blog is only as limited as your creativity. You don't have to write anything. You can use it as a medium to post pictures you take every day. Or even videos.
Web serials or web fiction are other popular blog styles. If you don't think your life is interesting enough to write about then make up some fictional characters. Each post can be the next installment in your story.
Review things if you have lots of suppressed opinions. Tell the world what you thought about a TV show you watched or a book you read. With ebooks and self-publishing changing the entire book industry, reviewers are highly sought after by emerging authors.
If you're good at something make a how-to blog. Explain the steps and explained what you learned from the last thing you created.
A blog doesn't have to be a journal of your personal activities. It's a medium. A way of sharing your ideas with the world.