This thread I'm using to compile bits and bobs for the artists for S&W.
Bits on sketching, pencils, inking, as well as composition and life drawing.
http://drawsketch.about.com/od/drawingt ... e-Library/
http://drawsketch.about.com/od/penandin ... shwall.htm
http://drawsketch.about.com/cs/figuredr ... ortion.htm
One thing strongly recommend is surfing the web for references.
If you like a certain artists inking style, find some pages of his work and print em out, that way you can look at the details of his style and techniques.
"How on earth do I draw water like that?" Well...find drawn images of water and pick the one you like the best and print it out. Pay close attention to how the piece was done: crosshatching, use of negative space, etc.
Have references handy.
Unless you're in that top 1% of artists, you don't know how to draw everything. Not from memory at least. Your hands aren't trained for it yet.
One of the main things that stop amateur artists from improving is ego and attitude towards using tools.
Photo-references and well...any references are simply tools. Same goes with the smudge tool on Photoshop and using certain pens and markers.
Once you're an uber-artists who can do anything and everything and are the Michelangelo of the 21st century, then you can have the ego to be an elitist and not use every tool and trick in the industry. Until then...you're in the trenches with the rest of us trying to improve, using every tool and trick available to do a good job.