Beginnings are easy. There are an infinite number of points for a story to jump off from and an incredibly large amount of space for it to expand into. Once that story trajectory has been mapped and well established though, its seems that the number of possible outcomes is greatly restricted - at least if the writer wishes to retain any sort of credibility with his or her story. Lazy writers can always employ deus ex machina to do their bidding of course, which opens up any number of possible, crazy endings involving ancient ground-dwelling lizard people or vengeful flesh-eating cyborgs from the far-side of Uranus. I try my best to avoid such drastic measures.
Endings are hard though, for me anyway. It might be due to my innate ability to abandon projects in their juvenile stage like so many unwanted children that I never really get around to attaching endings, thus limiting my practice in that area. So when I do write a story that represents a complete idea or at least a coherent thought process, attempting to place a resolution or something representing finality in the piece always leads to me either an abrupt, nonsensical finish or a rambling, unnecessary and heavy-handed concluding passage.
So I'm not sure what the secret is to wrapping stories up all nice a pretty. Maybe they just shouldn't be so. An ending that is easy to reach is hardly a destination worth traveling towards. I know its the journey itself that should make the trip worth taking but there needs to be something substantial, something worth seeing waiting at the very end for the weary reader. Even if its a just a realization, a new thought that was formed through the formation of a story, of a world created out of air full of breathing, fleshy things.