Bloggers who have an astute understanding of what they are
writing or the larger domain will always do well. Blogging is not
just writing. It is a fine combination of writing acumen, knowledge,
specialization, awareness of latest updates and an understanding
of what people or readers are looking for.
Choose a niche that you are comfortable with and equally
important is the readership. Do not pick a niche that no one is
interested in. You can write a blog on such a niche to satiate your
own desire but such a blog will be hard to monetize.