I'm about to give you pages upon pages of text.
There really are no rules to it. I mean, there are techniques that can help you, but the entire process is just different for different people, and the techniques are things that no one can really teach you.
I draw anime, and I started out just pausing whatever I was watching and drawing it. From there, I looked for lots of tutorials to teach me what I was doing, though tutorials, most of the time, didn't really help me. It was just a very gradual thing, and I had to learn most of these things for myself.
To get you ready for the progress, the earliest drawings I have of mine are these:
http://s286.beta.photobucket.com/user/happy_lil_chipmunk/media/Kimiko.jpg.html?sort=3&o=149
http://s286.beta.photobucket.com/user/happy_lil_chipmunk/media/img002.jpg.html?sort=3&o=107
Those are from the summer between seventh and eighth grade, a year after I started drawing. Back then I was proud of them, but now I have to wince a bit when I see them. The same goes for the drawings I drew in eighth and ninth grade, and sometimes even in tenth grade, just last school year.
This here is from last summer, though I wish I could show you something even more recent:
http://24.media.tumblr.com/tumblr_mcfhklYjyq1rjg6jyo1_500.jpg
I'll tell you now, a LOT of work went into getting here. I was drawing constantly (teachers had to say "put the sketchbook away" whenever I had a sketchbook. When I only had printer paper and the backs of worksheets, they took the drawings away.) and it was when I started drawing that I got a huge callous on my middle finger from the pencils.
The most important thing I could tell you do to is experiment. Some of your drawings will end up looking really funny, but others will have something in them that you sort of like. Learn to draw a lot of things in a lot of different ways.
Learn the difference between drawing with a regular pencil or a mechanical one: how they feel, which one feels better for what purpose. A regular pencil might feel and look better for shading while a mechanical pencil might make better lines. Start inking as soon as possible, even if it's with a cheap pen you happened to have on hand. (A while ago, a girl saw a drawing I was inking and asked what I used. I held up a regular old Bic Crystal and she was surprised, saying, "she isn't even using anything special!" A good utensil can make art easier, but you're the only one who can make your art better.) Learn what you like and don't like about any utensils you can get your hands on.
A lot of people try to acquire a style right away. Don't bother. Again, draw a lot of things in a lot of different ways, so that your skills will be broader. The style will get there later, and probably without you even noticing (:
Hope this helps you and prepares you for your journey as an artist :D
(One more tip. Get a tumblr, unless you're 12.9 years old or younger, and follow some art blogs, paying attention to what you like about some pieces, why you like it, and try your best to replicate it. That's how I learn different methods of drawing hair, eyes, mouths etc, and from there, I start to make my own that suit me.)