Yes: there's a sort of effortful waiting to the right art in the right place, just as there is to many other parts of the creative process.
You've got the draft down & you might think the major part of the work is done... but this is precisely where detail matters most.
One of the benefits of self-publishing is that you shouldn't have to rush. Of course, this could mean you don't get it done at all. (Rob Lang mentions this problem on another thread.)
So, OK, set yourself an artificial deadline: get it done; but understand that just because 'amorphous' creativity has turned into a 'project' (i.e. you know what you're aiming for), the game is not almost over. In terms of being an object, it's just begun.
I think a lot of the problems mentioned above come from rushing. There's the talent - award yourself some of this, even if you're not sure - and there's the will. And the will works slowly.