There are lessons aplenty to help with grammar and character arcs and plot development. These aren't those.
10. If you've blocked out a time for writing and you're writing well, the time will fly by in an instant. If you're not writing well, the time will drag on for eons.
9. Writing poorly is far easier than writing well.
8. Characters tend to speak loudest just as you're about to fall asleep.
7. If you're a morning person, you will write best in the evening and vise versa.
6. The realization of "This Is Crap" can come at any point. If you're lucky, it happens in the first 10,000 words. Let's just say I'm not all that lucky.
5. Even if you don't base your characters on anyone you know and the people in your life know this, it will not stop them asking "Am I in it?"
4. You will never read a book the same way again.
3. 85,000 words is a lot of words. A lot. You can't write it in a week. If you can, please go soak your head.
2. You will have all the patience in the world with your characters and very little with yourself.
1. People who ask "But what do you really do?" need to be abandoned on ice floes.