The same post 100 times
The best piece of writing advice I've received is: focus on a single idea. When you start writing, your mind will try to go off on tangent and add more points to your essay. But your writing will be a lot more powerful if you focus on a single thing.
If you're writing a blog, and feel like you're repeating the same idea across multiple blog posts, there's nothing wrong with that. Write the same idea again and again.
With every new post that you write you will learn something more. Writing is a tool for understanding. You will see things through a different lens, a different phrase or explanation will unlock something new in your understanding.
If you have observed a useful fact about life or your craft, write about it from all directions. Examine it completely. Steven Pressfield has built a career by writing about his idea of Resistance. He's written more than three books and thousands of blog posts revolving around a single topic. Many other great authors whom I admire have done this as well.