The longest I can do a pure contour drawing is about 15 min. I just can't stretch it out any longer. Please tell me I don't need to spend that much time on it, cause my hand just can't move my pencil that slow.
I usually didn't draw that long, either. However, it's all depending on how many fine detail you try to put in. Don't worry, just carry on in that book and return to that exercise later. When you've learned to see better and more your drawing sessions (also in blind contour drawing) will become longer. Relax, enjoy and draw!
Well, sorry, but the idea behind that is exactly to overcome what you're going through. If you can't handle fifteen minutes, you wouldn't make it for two hours, which is not only possible, but opens up a whole new road of observation. You do need to slow down and work on them that long, your question kind of proves it.
These aren't about good drawing, but just getting your eyes and hands to sync up (and really the mental processes you go through to do so), and to realize that you don't know all you think about the forms and things you're looking at. You've got to take this time to learn and see, or your drawings will lack insight about your subject over time.
Believe me, drawing this slowly now will free you up and make you faster before too long. You will learn what is important to include, to suggest, to leave behind, what is relevant not as a symbol which everyone else draws and you don't want to repeat, but as the essence, which few hardly ever see. To quote poorly, be one of the few.
Contour is actually a pretty bad method for beginning artists to start with. Also, "drawing on the right side of the brain" may actually hold you back because it teaches you mainly to draw what you've directly observed, rather than redesign based on what you know about anatomy, perspective, compositioning, and other principles core to drawing.
Check out and by all means possible, save, print up, and 3-ring binder this PDF: http://www.accad.ohio-state.edu/%7Ec...IGURE_draw.pdf
Read it, study/copy the figures in it, and learn all you can from it. It'll help your drawing skill far better than the methods in "Drawing on the Right side of the Brain."
Also, I'd say that you should spend at LEAST an hour and a half (with 5 minute breaks every 1/2 hour or so) a day, or ideally about 3-6 hours when you can devote time to really studying. Art is a deamanding curriculum that requires manual dexterity, a trained eye, coordiantion, mental (and physical) stamina, and lots of self-discipline. (Not to mention creativity.) Think of it as being an athlete, in that you need to practice regularly every day to keep your skill up and advance to the next level.