I also have teaching experience. I don't know how to monetize that, though.
Join as tutor in sites like udemy. iOS is most touted teaching skill and I am sure you make decent money if you put up some good courses. Start with couple of free courses on introduction. If they like it, they will surely buy your courses.
Join a startup which is well funded and have clear goal. Work there and use the free time for brain-storming. Having people around and listening to their problems are the best way for creating best products. Because you are solving real world problems. And if you feel have any semi-decent idea for app, post it somewhere, improve it and release it in iOS. It will generate some decent revenue and will lead to something else.