Paul Butzi and Gordon McGregor have been writing about completion inertia. Anita Jesse had a good post about general project inertia. I thought I'd chip in my bit.
I'm like Gordon and Paul - like to get going, prove stuff can be done, extract the goodness and move on. I'm not a completer by any means. Starting, however, is never a problem.
Here's my thinking: if it's not going to kill me or land me in jail, pretty much anything is worth a try. Certainly a photographic project has few negative consequences if it fails. If I have confidence in my abilities to do something, then I have confidence to get on with it. That confidence comes from proving to myself I have all the individual skill elements, I just need to bolt them together. So far, so good.
I've learnt that to complete stuff, I need to make the end run easy on myself. Line everything up ready for a quick blast for the finish line. In photography terms that means severl things. Knowing I have enough material for the project, being decisive in selecting and editing - first impressions, good is good enough - and a fairly mechanistic means of completing a layout (for a simple layout, I can go from list of selected photos to compeleted book in a couple of hours). Planning is key - lining things up for an easy effort. that bit i'm pretty good at.
thus my key strategies for getting projects done: having confidence in my ability to do the thing and clearing the path for an easy finish. This is a similar strategy I apply in my day job and it gets me past the main slow points.
To close, another from FDR:
Take a method and try it. If it fails, admit it frankly, and try another. But by all means, try something.