- You need an emotional punch. Your ending needs to harken back to the problem in the beginning. For example, if your protagonist's problem is he lost his job and is depressed, by the end of the story you need to address both the external and the internal problem. Did he find a new job? Is he still depressed? Thus, the conclusion of the story should specifically show the protag's emotional state, e.g. He smiled. You want to take the reader along on the entire emotional journey from start to finish. Don't assume the reader will get to where you, as the author, are. Bring the reader along via showing.
- Sentence order in the paragraph is important. Word order in the sentence is important. Studies show people pay the most attention to things at the beginning and at the end. And they tend to remember things at the end the most. Thus, if you can rearrange your paragraphs to have the most emotionally punchy sentence last it will have more effect. If you can rearrange your sentences to have the most emotionally punchy word last it will have more effect (still obeying grammatical rules, of course!).
- An overlooked writerly tool is: spacing on the page. A line has more emotional punch for the reader when it is isolated, i.e. surrounded by white space. Therefore, it can be very effective to give important lines their own paragraphs. Consider rearranging your final page. In particular, as an editor I often reccomend the last line of a story stand on its own:
See how the line alone is more emotionally punchy than when it was buried in a big paragraph?
It can take a story from good to great!