Most of the time, a trending news story will have one or more hashtags associated with it, so you can use those tags to help your post get more exposure. You can also direct your post to a particular person involved in the story with an @ mention.
Use an associated and relevant #hashtag to get more exposure
Use a topic with a direct relationship to your business
Create a funny meme rather than just commenting
Avoid storied that are controversial, tragic, or depressing
Don’t limit yourself to the more obvious news stories
Don’t take advantage of tragedies but approach tastefully
So what kind of news stories are jackable? Topics that have a direct relationship to your business are ideal.