Drawing

"Art probably owes more to form for its range of expression than to color. Many of the noblest things it is capable of conveying are expressed by form more directly than by anything else. And it is interesting to notice how some of the world's greatest artists have been restricted in their use of color, preferring to depend on form for their chief appeal. It is reported that Apelles used only three colors, black, red, and yellow, and Rembrandt used little else. Drawing, although the first, is also the last, thing a painter usually studies. There is more in it than can be taught and that repays constant application and effort. Color would seem to depend much more on a natural sense and to be less amenable to teaching. A well-trained eye for the appreciation of form is what every student should set himself to acquire with all the might of which he is capable."

~ Harold Speed The Practice and Science of Drawing

I have lately had the great fortune to converse with quite a few professional artists.  The consistent message has been to draw well. See form--really light and its absence--and negative space. Painting is drawing with a brush.

Sometimes when I am painting, applying color, I feel lost. Is this color lighter or darker than this color? How dark is this color in shade? How does the color's hue change in shade? And so I imagine that if I feel confident with the values sans color--just pen and ink, ink wash, graphite--that I'll have some foundation for color.

And of course there is one more advisement... Practice!