Ditto what has been said by several people already- shoot, shoot, shoot and shoot more. Then get yourself in the darkroom and print, print, print and print more. The only way you're going to get a feel for what the tools will do is to use them extensively. When you've shot and printed enough, you'll just KNOW when you're looking at a scene how it will render on film and on paper. You'll know when looking at any given scene if you'll have blown-out highlights or detail-less shadows depending on which way you expose, and which of those is the lesser of two evils for what you want to achieve. Or if a scene will render so flat and monotone that you can't coax either a highlight or a deep shadow out of it, and if that's what you want also.
Just get your feet (and your hands) wet and do a lot more.
If you want a visualization exercise, go find the work of some photographer whose work you like, and study it carefully. What do they focus on - is it abstract patterns and design, is it movement, is it detail, is it sweeping landscapes? Whatever it is, go out and look for that, and shoot that way. Take it as inspiration, not something to copy. If you find someone's use of texture interesting, then go out and look at the world from the perspective of looking at the texture of things. Look at how light creates and obliterates texture. Pay attention to the kind of light that creates the effect you are drawn to - is it flat, is it hard, is it bright, is it soft? Is it direct, is it oblique? Pay attention to how you are seeing these things when you notice them - are you close, are you far, are you looking down, or up? When you start thinking about HOW you see, you'll have a much easier time figuring out what to photograph. You'll quickly find yourself ALWAYS wanting to have your camera on hand, because you'll be seeing things everywhere, all the time.
