Two great things from this interview:
So, when people come to me and say they want to be a writer, "What should I do?'
I say, "You have to write."
And sometimes they say, "Well, I'm already doing that. What else should I do?"
I say, "You have to finish things...because that's where you learn from. You learn by finishing things."
If you only write when you're inspired you may be a fairly decent poet but you will never be a novelist because you're going to have to make your word count and those words aren't going to wait for you whether you're inspired or not. You have to write when you're not inspired and you have to write the scenes that don't inspire you.
And the weird thing is that six months later, a year later, you'll look back at them and you can't remember which scenes you wrote when you were inspired and which scenes you just wrote because they had to be written next.