When it comes to writing blogs, Search Engine Optimisation is something not everyone focuses on. Many times we would come across blogs that have good content yet don't rank well in searches.
The reason behind is simple, Search Engines crawlers don't think your content is good enough to be ranked higher. So how does that work?
In order to rank well in the searches, you need to make quality content and focus on your niche. It is never a good idea to spread your hands in all directions. Doing so in blogging and writing content on anything you find can backlash as well.
You see, if someone visits your website for a particular search term and some other person searches for something remotely related to that particular search, they tend to believe your blog might be rich in that particular type of content.
In simple words, you would not expect a Video Editing related blog to host content on Astrophysics, would you? So if someday a the Video Editing blog decides to write on astrophysics just because they like it. Does not mean it's would be ranked better on searches because the search engine knows that their blog doesn't contain a significant amount of quality and quantity of astrophysics related content.
Doing so this also reduces the authority of your blog because this reduces your search ranking.