Try and do something ambitious in the world, and when you find a huge obstacle, conquer it, and turn your method into a startup.
I always try to find the problems I have in my daily life otherwise I miss them. Browsing websites like Product Hunt or trying to find new technologies to you are great as well. For example, when you don't have any knowledge about ML/AI and see Microsoft Azure's web site, you know you can use ML/AI with ease, then you may be able to get ideas!
I had this realization that make what people want startup mantra is not enough. We gotta find what people want, but it should be different or 10x better than existing ones.
Solve a problem that you have. Or try doing some keyword research and see where there is some demand with low comp