Ask HN: Tips on how to drive a blog

Hey guys, I have a blog that I write seldom, even wanting to write often.

Few time ago I figured out that it happens, because I don't know in which subject to focus and I'm "afraid" to mix subjects like enterpreneurism, marketing, startups and technical articles in a single blog.

From you opinion, is it a good idea write about all this subjects in a single blog? Is it better to focus in some of them?

Thank you guys for you help.