If I see an ending, I can work backward. ARTHUR MILLER
I read foreign newspapers as well as those in the U.S. I find articles are great story prompts for story lines as well as ideas for characters. Recently George Marèas in his blog for Le Monde, Police et cetera, http://moreas.blog.lemonde.fr/2010/05/24/taser-contre-kalachnikov/#xtor=RSS-32280322#xtor=RSS-3208 wrote
En effet, à quoi un Taser peut-il bien servir face à une Kalachnikov !
In effect, how does a Taser serve well when faced with a Kalashnikov!
How, indeed? The situation is just where your protagonist should be at the crisis of the story—completely out-gunned. How do you get there? The best way is to fully develop the character of your antagonist.
However much work you put into your protagonist, do the same for the antagonist. Make certain that the antagonist has powers, skills and an intellect that at least match your protagonist. Better yet, make them more than your protagonist has. Make the antagonist seemingly unbeatable and unstoppable. By doing this you will automatically build tension into your story. Write all the details. Create a back story. Give him a hobby. Write a monologue. This all takes time and is…well…work. But, the more your create the background the more you have to work with as you tell the story.
Tension is what keeps the reader turning pages. Tension is what you want in your final climax scene. The best way to see the ending is to envision a fully developed antagonist to challenge your protagonist. How is your protagonist armed with her figurative Taser going to beat the Kalashnikov facing her?