Creativity is connecting things that previously had no reason to meet.

Novelty rarely comes from inventing something out of nothing. It comes from putting together two things that had no previous reason to be near each other: a method from one field applied to another, an idea from your reading meeting a problem at work. The parts are usually old and the connection is new.

Widen your inputs deliberately rather than going deeper into one area. Read outside your subject, talk to people who do different work. Then, when you are stuck, ask what an unrelated field would do with this. Most of what feels like inspiration is this connection happening quietly.