I agree that you should draw what you're passionate about. You like comics? Just draw some. Understand that art takes decades to get good at though. Art is a deep and complex set of many different skills that take literal lifetimes to understand, and you're never finished learning it. Being an artist means always being a student.
Something that teaches you many of these skills at once is drawing from life. Perspective, anatomy, drafting, lighting, form, how to reduce complex shapes into simpler easier to understand shapes, reflections, refractions, radiosity, I could go on for hours about all the things drawing from life teaches you. It can be boring sometimes, but constantly studying real life is one of the key tasks to becoming great at art.
Also, if you want to be good at art, you've got to be completely obsessed with it. You've got to be thinking about it all the time. When you're hanging out with someone, you're thinking about the anatomy of their face. When you're about to eat your dinner, you're examining the highlights in your mac and cheese.
I made a video about this exact topic a few years ago, maybe it'll help:
