Ooo! Ooo! I know this one! I agree with pretty much everything that has already been said. (For what it's worth, I have an art degree.)
You should know that there are two kinds of drawing: both are important and valid.
1. One is 'academic drawing'. In one sentence: Draw what you see, not what you think you see.
This is the stuff you learn in art school: draw the still life, draw naked people from observation, never trace, never use photo references, don't work from memories of anatomical models. Those rules are broken all the time in art programs, btw, especially the last two, since they can teach you how to see things you wouldn't notice otherwise.
2. The other is 'illustration work'. In one sentence: Everything is a formula you can learn, but if you can't learn it, trace it.
This is how manga can be churned out at a chapter a week, this is how graphic designers put food on the table. Don't let anyone tell you to be ashamed of drawing this way: it is a powerful tool for telling your stories.
Examples:
Everyone has seen 'anime eyes', but they work just fine for communicating emotion. Even though you can reduce it to a formula from "How to Draw Manga". Copying the formula is just the start: you need to practice it again and again to learn what the different parts of the formula. You'll have a head start in figuring that out if you study academic drawing, but ultimately it's just experimenting by drawing again, and again, and again. Studying examples really, really helps: for eyes you need to study Kōsuke Fujishima and Tite Kubo. Fujishima makes very very small changes in the negative space around the iris communicate very specific emotions. Kubo uses a handful of shadows defining the muscles above the eyes and between the eyebrows to communicate different ones. They are geniuses, not for their artistic skills, but for figuring out how to get the most amount of power out of the least amount of lines drawn. Having crazy deadlines helps with that - a lot!
Truth time: nobody ever got any good at drawing things they didn't care about, UNLESS they liked light and dark, texture and form for it's own sake. This is where the academic drawing types are coming from. The people who loved the characters from the manga and comics they read - they are the ones who got really good at illustration work. Poke around in the extras for Porco Rosso and Spirited Away - there's some clips of Miyazaki sketching things. He makes it look stunningly easy, but that's due to decades of learning what things actually look like (academic drawing) and having to make stuff up quickly (illustration).
Advice time:
Only love gets around boredom. You'll need a favorite picture of a favorite character to start with. Go ahead and copy, line for line. Have fun with it. If you stop having fun, stop drawing that character, and pick a new one. Iterate. Go back the next day (not the same day) and pick the part you want to work on most. Take a second look at what you're copying and ask yourself, 'hey, how does that work? Is he using the exact same chin again? Does she really only use three poses? See what the shortcuts are, and take them.
If you love just losing yourself in the drawing and the seeing, that's a different kind of love. That love will help you learn academic drawing. Try the book "Drawing on the Right Side of the Brain" - there's a website here http://www.drawright.com/ that gives you a taste. You can skip the theory if you want, and just check off the exercises one by one. You'll find yourself seeing a world you didn't realize was in front of your eyes.
