I've come across quite a few writing advices over the years, some very valuable and some of which I didn't approve at all. Most of them, however, made me think through important issues. Adding a few of my own experiences, I've arrived at the following list:
1. The best stories are those emerging in the reader's mind. The text should initiate such stories, and not get in the way.
2. Don't let language and plot fight for attention. When one claims its space, hold back the other.
3. Direct the reader's attention with care. Lead her gaze, but let her reflect for herself.
4. Every character in the text should be there for a reason. Everyone should possess a personality, a life and a history, even if none is mentioned. Delete the characters you don't really care about.
5. Beware of adjectives. Used sensibly, they clarify and add color. Used carelessly, they turn into stumbling blocks.
6. Whenever a sentence or a paragraph feels wrong, try to a) remove it, b) cut
words, c) change the order.
7. Twist and turn your sentences. Divide and merge. Move words around. Experiment and observe.
8. Flow and rhythm matters, as does the sound of words. Try reading out loud.
9. Mind the tense of verbs, especially in retrospective scenes.
10. Don't abuse dialogue to spoon feed the reader.
11. Write only what you would like to read.
12. Put your draft away for a while, then read it again, and edit. Repeat until done.