I break down my drawings into three categories: pencil on paper, ink on paper and ink over pencil.
Pencil on paper- This is the easiest to explain. It is what we have all done. I get a piece a paper, I get a pencil and aI draw on the paper. It actually gets a little more complicated than that with my choice of pencils. For my small drawings, say five by seven inches, I usually use a 0.7mm mechanical pencil with a B or 2B lead in it. I use the mechanical pencil because my small drawings are all about the line. A mechanical pencil isn't an especially versatile tool (a normal wood pencil is better for shading or mark making) but it is great for a smooth consistent line. Well, as long as that line is small as in my little drawings.
My larger drawings, eight by ten inches and up, get drawn with a normal pencil that everyone is familiar with. The pencil isn't a wooden, painted yellow number two pencil with an eraser on the end that we all took our grade school tests with but it's in that family. Drawing pencils are labeled according to the softness of their lead (graphite, actually but I'll stick with the tradition of calling it lead). A 7H is the hardest and as the number gets lower the lead gets softer. After you reach 1H the scale switches to 1B and the number now rises as the lead gets softer until you reach 6B, the softest lead of all. H's are hard B's are soft. I use a 4B or a 6B depending on the paper I use. I use the soft leads because I like the line to come of my pencil with little effort. When using a harder lead I have to bear down with more pressure and I end up gouging into the paper instead of drawing on its surface. One of the consequences of a soft pencil is that it makes a darker line by leaving more graphite on the paper. This means that I have to be careful not to rub my had on the paper as I'm drawing because I'll smear all the lines and make a big mess. But the trade off is worth it.
Ink over pencil- This type of drawing is a legacy of cartooning. Traditionally comic books and comic strips were all printed as cheaply as possible. This meant that a pencil drawing could not be reproduced well because a pencil drawing is really shades of grey and for printing black is needed. This is where inking comes in. The artist would take a brush, (or a an old fashioned ink pen) dip in ink and go over his pencil drawing redefining it in ink. It was this final ink line that was reproduced as the comic strip. As a consequence the pencil drawing was not considered a finished drawing and things would be left out of it because they would be added in the ink stage.
Ink on paper- This differs form ink over pencil in that there is no pencil drawing to use as a guide. I start with a blank piece of paper, a brush dipped in ink and then I start drawing and see what comes out. Sometimes I'll use white paint as an eraser to change parts of the drawing. This type of drawing is all about trying to bring new images out of my imagination. I don't even start with an idea of what to draw, I start drawing an then see what I think it is. The idea comes from the marks I put on the paper. This a great way to pull strange and different images out of my brain that don't come from a conscious place. When using a pencil I can search around for line and erase and redraw until I get what I'm looking for. With ink straight on paper I've got to go right for it. Make marks, react to them and turn it all into a drawing.