I've discussed story beginnings multiple times, but I haven't discussed story endings as often... I did discuss it here.
The point is story endings are important.
The most important thing about a story ending is it needs to address the problem you introduced on page one (you introduced a problem on page one, didn't you?). I'm a little embarrassed to admit sometimes when I'm writing a story I end up solving a problem that wasn't introduced on page one. But the magic of rewriting enables me to then change the problem on page one. :) Violà! My story solution matches my story problem.
Another important element of the story ending is the emotional payoff. Take a moment and show the protagonist reacting to the conclusion. Is he/she/it relieved? happy? sad? injured? Whatever it is, what does the protag think/feel about it? Show it!
Good luck with your story endings!