I came to the open thread to add a comment saying "Everyone should read Steven Pinker's The Sense Of Style". I didn't know I'd have the perfect occasion.

There's no overarching coherent theory, but there are ideas both at the detailed level of choosing words and at the higher level of structuring your writing and taking your reader on a journey. I also enjoyed reading it immensely and found it very hard to put down. Everyone here writes, so everyone here should read it!