Whatever you’re interested in. Whatever you’re passionate about.
Whatever you want.
Blog about things you have feelings for, positive or negative.
What do you love? What do you hate? Channel those emotions into energy. Energy spent on blogging.
There’s really no limit to what you can blog about. Except the limit you place on yourself.
If you want to blog about something, blog about that something.
Besides, if there’s a blog post you want to read, but it hasn’t been written yet, write that blog post.