From the Guardian UK:
What’s a good science story?
Something that makes me think, “Wow, that’s amazing!”. That is, stories about exciting new research that reveals some new insight into nature. The natural world is a wonderful, complex thing, and scientists try to divine its little secrets. A good story should not just explain the science simply and clearly, but also convey this wonderment.
What do you need to know to write well about science?
How to tell a good story. That requires a good grasp of language, some understanding of the science you’re writing about, and an ability to “translate” technical information into plain English and write about it compellingly.