I have no interest in blogging, but I’ve seen people on these forums asking to start, and they all seem to be approaching things backwards. The first question they ask is “What should I write about to make money?” My answer to that would be: nothing. If your only interest is to make money, you’re unlikely to write things that others will want to read, and if you have to ask what topic(s) to cover, chances are you don’t have not enough knowledge in the relevant field to produce anything worthwhile.
There are good reasons to start a blog. For instance:
“If I write articles showing people how to use the products on my site, will people find it useful?”
“I have a fascinating collection of 18th century silverware. Maybe people would be interested in reading about it.
“I love to write. I will blog about my activities for my own enjoyment, and maybe others will enjoy it too.
All positive reasons, and none of them centered on making money. If the blog is making money or increasing your sales, that’s an added bonus. That shouldn’t be the goal, as far as I’m concerned.