A graphics pen and tablet (I use the Wacom model) is used to add detail and to give the lines more character. A more hand drawn look can be achieved with a graphics pen.

It takes some practice using a graphics pen to be able to draw in a freehand style. Traditionally when drawing freehand, the artist is watching his hand and the surface being drawn on at the same time. To draw with the graphics pen, the artist is looking straight ahead at a monitor, while drawing on a tablet that is probably somewhere well below the monitor. Well, that's how I do it anyway. Some artist place an image on the tablet and trace it (the pen will work through paper up to half an inch thick).

Tip:
Tape a piece of paper on the drawing surface of the tablet. This gives the surface some tooth and better control of the pen.

Fact:
I never try to do an entire drawing by drawing freehand with a graphics pen. I might start with a scan of a very tight pencil drawing and use the graphics pen to clean it up, or I might use the pen just to add some details.