You've started ... but will you finish?
I would guess that a third of the people I coach have issues with finishing work and/or writer's block. It would be a lot higher, but I limit my exposure to these problems, as they drain the coach more than anything else, and it affects my writing if I spend too much time working with others who can't get to the end of a story.
There are a lot of techniques that can help - but the beginning of help is a harsh lesson. There is no such thing as writer's block. I know that's not a nice thing to say, but I believe it to be true. There is no waitress's block, no dancer's block, no surgeon's block ... and there is no writer's block. What there is though, is writer's impediment, and it comes in one of three forms, in my experience:
1 - you revise your work as you write (see last post about creativity and analysis)
2 - you don't know what the end of the story is going to be
3 - you're scared of something
I've already covered 1, so I won't go into it at length here, but if you're a committed writer/reviser, here's a trick to help you recognise and change your behaviour; it's one that has worked for many of my students.
Find a small, stiff, piece of card, and on one side draw a cake bowl with ingredients around it. On the other draw a beautifully iced cake. If you can't draw, cut pictures from magazines or use clip art. When you are writing, you are making a cake - when your cake is made, you can ice it. You KNOW you can't ice a cake that hasn't been baked; the whole idea is ludicrous, isn't it? So why do you try to revise your work before you've finished it? Use your cake emblem to patrol your working behaviour. When it's baking side up, you should only be writing, not revising. When it's icing side up - and only then - can you go back and revise what you've written. And it should only be icing side up if the story you're working on has -the end- typed on the last page. Otherwise, you're still baking! One of my students (a non-baker) has a switch emblem instead - one side shows 'write' and the switch in the up position, the other shows 'edit' and the switch in the down position - it works for him.
Next time, knowing where the story ends ... and how to get there!