The best time to negotiate your salary for a new job is the moment AFTER they say they want you, and not before. Then it becomes a game of chicken for each side to name an amount first, but it is to your advantage to get them to give a number before you do.
"I hope that in this year to come, you make mistakes. Because if you are making mistakes, then you are making new things, trying new things, learning, living, pushing yourself, changing yourself, changing your world. You're doing things you've never done before, and more importantly, you're doing something."