How do I make my writing sound like a college textbook, a newspaper article, a scientific journal, a blog post, etc, professionally?
2 Answers
Practice pastiches.
Pick examples of the style you want to emulate, and then write something like that. For instance, take a newspaper article about the opening of a library and write something in its style about the opening of an imaginary school. Pick a blog entry about visiting parents for the Fourth of July and write one like it about visiting grandparents for Labor Day. Etc.
Publishers sometimes have a standard and recommendations on how to write an article for them, as freelance writers submit articles and need to know in what style to write for them.
As there are a myriad of possible styles, I recommend searching for them yourself, (rather than me providing a bunch of links).
This is especially true for news articles, academic papers, and whatever else. The good way to learn, is to write a draft and then go over it again to match a set of guidelines.