I don't know if this is considered smart or stupid, but I find myself working on multiple projects at the same time. I have completed my second novel, though I still plan to pass it through a copywriter for final editing. I am almost done with my second to last revision on my first novel. I usually do my revisions in the mornings and look forward to completing it. Last night I completed my first draft on the first chapter of a new book. I also have a couple other books started, and several other outlines underway.
I am definitely running the risk of spreading myself too thin to ever finish anything, but usually, I reach a point where I need to mull over what I have done before I continue. Sometimes this is a point where I'll switch gears and make some contributions to another story. I find that writing out the first couple scenes usually gives me some insight on how my characters are going to develop. I like to keep it more right brain than left.
I do use a piece of software that lets me organize my scenes and chapters, and move them around. In fact, without this, I probably would never have tried working on so many manuscripts. It allows me to define my chapters, then sub-define them in scenes. I can create notes about the scenes and the characters and then come back to the project at a later date, I hope.
So, maybe I'm doing myself a disservice, I don't know. If I finish this new book (I expect it to be shorter, perhaps a novella), then I guess my technique is working for me. If I actually pick up where I left off on one of my others, then I can be sure of it.
I think I said "I" 25 times above, so I(29) am going to stop now.