A couple months back, I was asked to come up with some "writing tips and tricks to inspire students to get creative" for the DePaul Blue Book, a blog created and maintained by the Departments of English; Writing, Rhetoric, and Discourse; and Journalism.
I basically give writing advice all day every day, but I'm keenly aware that every time I say something, I could easily find ten examples of when that something wasn't true. So, you know, writing advice is tricky and should always be packaged with a grain of salt.
In the end, this is the one I decided was the most fundamental (while still not always being true). It's pretty straightforward - the kind of thing you'd think you'd master after time - but I gotta say, it's also the one I keep coming back to.