I've been working for the past year on a new sci fi/fantasy novel. In fact, shortly after leaving the USCCB, I had an incredible creative spurt in which I basically wrote the whole thing. And since then I've been tweaking and rearranging and working on the story.
The way I tend to do it is to force myself to complete a draft of the story and then begin to work on details and research, etc. My theory, for my style of writing, is that the longer the novel takes the better. The more time I have to work on it, the better I can make the story and the clearer the writing is.
In the past year, I've fought off urges to wrap it up and begin searching for a publisher.I'm glad I did that because I have decided to scrap the ending and re-write it. I am also leaning towards scrapping the beginning and re-writing that, which would affect lots of stuff throughout the book. One interesting thing for me has been the mental work involved. When I was younger, for some reason, creativity took little or no effort. Now, I find that creativity by itself, alone, does not satisfy and I spend hours racking my brain for solutions to storyline issues. I do not get Eureka moments. Resolution is generally slow and painstaking, but progress is made. It's just a new situation for me and it'll take some getting used to. I've put quite a bit of mental energy into this piece of work than I expected to originally. (Also there is time travel issues involved. I hate time travel.)
The other aspect to this is that I want to get an established sci fi publisher this time, so I am paying more attention to the story. Also, I have no movie pretensions about this one. It wouldn't make a good movie, at all. Many writers see their work in its potential movie format and that has an effect on how the story is written, not necessarily for ill. In this case, it clear to me right from the beginning that I could not entertain any such film dreams, as remote as the possibility is to begin with, at all. So the work continues.