Is there any way to develop a decent sense of composition or colours or even some sort of mindset like visualizing figures and such without having to draw them out or something? I dunno, I've seen plenty of methods and such that a lot of good artists use but I feel like I'm missing something really, really basic because I just cannot get any good results when I try to draw. Something that's probably common knowledge to everyone else but I'm too dumb to notice...

Answer: draw more, reference things

I’m not lying, that is absolutely the answer. I have dozens of sketchbooks filled with tons of stuff- you ought to fill at least 5-6 sketchbooks and then see where you’re at, making an effort to step out of your comfort zone.