According to: (The Guardian)
1. Richard Ford: Marry somebody you love and who thinks you being a writer’s a good idea.
2. Elmore Leonard: Never use a verb other than “said” to carry dialogue. The line of dialogue belongs to the character; the verb is the writer sticking his nose in. But “said” is far less intrusive than “grumbled”, “gasped”, “cautioned”, “lied”. I once noticed Mary McCarthy ending a line of dialogue with “she asseverated” and had to stop reading and go to the dictionary.
3. Neil Gaiman: Fix it. Remember that, sooner or later, before it ever reaches perfection, you will have to let it go and move on and start to write the next thing. Perfection is like chasing the horizon. Keep moving.
4. Margaret Atwood: Take something to write on. Paper is good. In a pinch, pieces of wood or your arm will do.
5. Al Kennedy: Read. As much as you can. As deeply and widely and nourishingly and irritatingly as you can. And the good things will make you remember them, so you won’t need to take notes.
6. Helen Dunmore: Finish the day’s writing when you still want to continue.
7. Geoff Dyer: Keep a diary. The biggest regret of my writing life is that I have never kept a journal or a diary.
8. Anne Enright: Description is hard. Remember that all description is an opinion about the world. Find a place to stand.
9. Esther Freud: A story needs rhythm. Read it aloud to yourself. If it doesn’t spin a bit of magic, it’s missing something.
10. Neil Gaiman: The main rule of writing is that if you do it with enough assurance and confidence, you’re allowed to do whatever you like. (That may be a rule for life as well as for writing. But it’s definitely true for writing.) So write your story as it needs to be written. Write it honestly, and tell it as best you can. I’m not sure that there are any other rules. Not ones that matter.