The first manuscript I actually finished was "The Crypts of Denver". It was inspired by one of my many strange dreams; one that I remembered well enough to take some notes on.
Some of the elements that contributed towards the manuscript actually getting finished (in no particular order):
- a strong drive to finish it, from the moment I woke up after having the dream
- steady support from my wife to keep writing
- setting aside time to write regularly
- writing out the outline for what would happen very early on in the process, even though things changed dramatically as I went on
- being a very fast writer when I know where I'm going
It took me about a year and a half to finish the manuscript, though that was more due to the rest of my life than the writing. The great majority of it was finished in 3 months once I started making more time available for it. After that experience, I'm pretty confident that I could finish the first draft of a novel from start to finish within 3 months without stressing. I picked up a lot of lessons along the way.
I started sending the novel out for queries to agents - very slowly. Rejection letters are tough, but the first person I queried (Nathan Bransford) was extremely helpful and sent some quick notes as to why he rejected the partial. If nothing else, I was certainly pleased to have rated a partial on my very first query. It's been quite some time since then (I didn't query for it for about a year), and though I've rewritten the opening extensively I'm not sure if I want to requery on it to the same people I originally did or not. More likely, I'll wait until I finish my next novel before querying again.