The November update of ArcGIS Online (read more here) added a bunch of improvements and some exciting new features (like the beta Vector Tiles). Along with these came some changes to the story map tools. These are focused on making it easier to create your story map and include tools that; check for issues, notify you and give you information on how to fix them. Getting this kind of feedback while you're working on the story map saves the frustration of thinking you are done only to discover a mistake when you review your handiwork. On a similar vein you can now create and edit web maps from the story map builder mode for either Story Map Journal or Story Map Series.
But don't forget the most important part of creating a story map. We got a reminder of this at a recent team meeting, where we were split into small groups and challenged to create a story map. A good user interface and clear cartography matter - but the most important thing is an engaging story. I'm a sucker for stories of exploration like Shakleton's but people are also creating interactive reports to tell the stories in their business data. NHS Scotland's Public Health Observatory have created one to replace their paper reports and NHS Scotland have put together a regional map.