Drawing negative space.

During my time at Alfred State, I had a professor who was one of my biggest inspirations. She taught me more than any other professor has about life, and about art itself. She really made me start viewing the world in a different way. Still today (2 years later) I find myself doing little habbits she taught our class to do while we were creating art pieces. She truely had corrupted my mind in the best way possible.
One of the most important lessons she taught me was about viewing the world around you. She had all of us go outside (she taught quite a few lessons outside when the weather was nice) and she had us each focus on a brach with leaves and start to draw it. We all drew these branches with leaves, which were very good, but she pointed out how inaccurate the distance between each leaf and twig was in our drawings.
She then told us to look at the branch, and instead of drawing the object itself (the leaf, the branch, the twigs) focus on the negative space between the objects and the size. Do not look at the object itself. This really makes you look at things differently. Like what shapes make up the negative space between objects, and it really helps you with porportions. The image you come out with is not going to look like a normal piece it will look odd, but it is very good practice and it will train your eye to look at every piece of a picture.