Good writing begins with asking a question or pursuing an idea that you want to explore more deeply. Imagine what the world would look like if it became your perfect utopia - what benefits and challenges would arise? On the flip side, imagine what the world would look like if your biggest fear became a reality. How would you cope, survive, or thrive?
Whatever genre you want to write in, world building is necessary. Start by considering what you want the world to be like, or what you're concerned may happen to the world, and make a list of questions. I've provided some examples below to get you started.
What would the world look like if we rewarded more substantial jobs? For example, what would the world look like if we paid teachers and nurses more than we paid entertainers or athletes? What would that say about our society? How would our society function with these rules?
What would happen if we elected a woman president? How would the public react? How would our country function differently? Would different policies or issues be prioritized than what is deemed important right now?
Of course, these are questions I would ask to get me started. Other writers have started from places like, "what would happen if spiders became three times the size of humans and took over the world?" Any question is game, nothing is too outrageous.
What questions would you start with?