It took seven and a half years of full-time effort to get my first yes. I went through an especially tough time about four years into it. A really, really bad time. A sort of, "Am I really going to keep doing this?" kind of bad time. And for a gal who never wanted to do anything but write, that was pretty darn bad.
Talking to a fellow writer recently, I tried to explain what got me through it. And the best way I could think of to describe it was that I broke up with the past. I broke up with the four years that had come before. I broke up with every person and situation that had dashed my high hopes. And, as you always have to do at some point following every breakup, I said, "Aw, screw you, anyway. I'll be just fine without you."
And I went back to work.
I had to nearly double the amount of time I'd already spent writing before one of my novels was acquired. But there was something about what I'd done...after that breakup, I was in it for the long haul. I'd dug in, and I wasn't letting go.
And man, am I glad I dug in. I can't imagine a life without writing...