The ability to learn coupled with the willingness to adapt. More specifically you should look to balance out what you already know with something new. If you s

The ability to learn coupled with the willingness to adapt. More specifically you should look to balance out what you already know with something new. If you spend your weekdays making CRUD apps, don't spend your free time investigating (yet another) different way to make a CRUD app. Learn machine learning, operating systems, etc. For an actual field, I would think anything to do with large amounts of data, whether it's machine learning, data visualization, etc.