Writing a blog with a particular niche doesn’t end with just the unique content, it also requires the perfect keyword that will fit to your niche. The keyword is what you should rank so when people search for a particular keyword your blog or site will be first on the line and if your blog is the first on the line, people are likely to click on it.
The keyword that you should have must go with your niche and not just a keyword that you like.
“You can’t use “scuba diving” as your keyword in an entertainment blog”.
If you want to know a keyword density, or how many searches for a particular keyword has based on time, you can use the Keyword Tool from Google.