The secret of good writing
It may seem self-defeating, but I think part of my job is to help people develop their own writing ability. Recently I discovered The Secret of Good Writing, articulated as clearly as one could wish. It's the first paragraph of the Fowler brothers' book, "The King's English", first published in 1906. (In that time, they used the generic pronoun "he", so the politically correct should brace themselves.) It reads:
"Any one who wishes to become a good writer should endeavour, before he allows himself to be tempted by the more showy qualities, to be direct, simple, brief, vigorous, and lucid."
I can't improve on that. If you'd like to see what more the brothers had to say (and it's well worth it), go to my Bookshelf page and you can order the book there (via Amazon).

