Creative acts require a decision to complete; otherwise they can go on forever. That is: that novel you’re working on won’t ever be finished. Even if you see it in print you’ll still have edits & additions you’d make if you could.
The difference between ‘published’ and ‘not’ is your decision to call it done.
Here’s a trick: whatever you’re working on, break it into pieces. However, be sure that those pieces have definite ends based outside of your head. Sticking with the example of a novel – try writing like the serial novelists of the 1800’s. Dickens published a chapter at a time. He had a monthly deadline to meet; one that he chose but, once chosen, had to be met every month lest his publisher and readers take serious issue with him!
Whatever your creative endeavour… remember the wisdom of Glengarry Glenross:
RT @tmorello: "People call me a feminist whenever I express sentiments that differentiate me from a doormat or a prostitute."-Rebecca West, 1913 - jameskupka03/09/2010