In no order whatsoever (that I can discern), here are the ten best pieces of advice I have ever received on writing.
1. A good writer uses verbs and nouns, and makes use of adjectives and adverbs only when necessary.
2. Honest writers admit they want others to read their writing. Anyone who says otherwise is kidding themselves and is probably on some sort of medication.
3. If you can make a sentence (paragraph, chapter, book) shorter, and still say what is necessary, you should.
4. No one starts writing with their own style. Therefore, start writing by copying the style of those you admire most and avoid the style of those you admire not at all.
5. All good writers are good readers. Not all good readers are writers. If you can find out why one is true and not the other, you may be a good writer.
6. Never edit your writing until the first draft is done. Then, edit that draft until it allows no more editing.
7. Always write in the active voice.
8. Learn the rules of grammar, syntax and punctuation so you will know the perfect moment to break them.
9. There is no true work of fiction. Every novelist and short-story writer has some truth in every character, setting and plot device. Conversely, there is no true story either. We each store memories with our own bias, unable to see around us accurately, oblivious to that which others see.
10. The only way to produce good writing is to write a lot of mediocre material and learn how to make some of it good.