You aren’t going to get very far if you spend your entire career trapped in your own head. The inspiration that leads to great works often comes from outside of ourselves, whether we know it or not. Be willing to “step outside” and take a look at other stories for inspiration.
You know what, I’ll do you one better, don’t just look at other stories for inspiration, look at everything that surrounds you. Most of our “new” ideas are just creative retellings of a lot of older ideas, things that we picked up and were influenced by that we didn’t even recognize at the time. A good illustration for that can be found in this mock retelling of the creation of Star Wars.