I generally agree with the point that there is no correct diction; it depends on context.
However, I think that everyone could benefit from reading Strunk and White’s The Elements of Style. In my opinion, every English writer in the whole world should be required to read this book. It’s the bible of concise, direct and expressive writing.
Some people may find it a little too dogmatic, and it certainly doesn’t hurt now and then to stray from its basic precepts, but on the whole you should write in a way that conveys the most information with the fewest words.
I have referred to this book time and time again when doing any kind of professional writing, and I give it a lot of credit for improving my writing both in college and now.