Probably the most fundamental discipline involved in drawing is learning how to draw what you see.  Contrary to popular misconceptions, this is not just a matter of manual ability.  the physical requisites for drawing are minimal: average sight and average manual dexterity.  Drawing is a matter of seeing through the mind, of comprehension, rather than of 20-20 vision and deft fingers.  We don't consider the requisites for being an adequate draftsman, the kind of person who is able to look at an object, analyze quickly the relationship of size, shape value and texture and create a set of relationships on paper which will graphically describe the perceptions. 

You need to analyze what differentiates the seeing involved from learning to draw from the seeing that lets you move about and identify objects in daily life.  We exist in a three dimensional world and we apprise objects in terms of their three dimensional character.  It is always difficult for a beginner drawing a cube at eye level not to show the top place of the cube, because he knows it's there even though he can't see it.  It always comes as a shock to discover that when we look at any object except a sphere, it looks different each time we look at it from another perspective.

Much of learning to draw consists of learning how things look rather than how they are.  It isn't until we begin to draw that most of us discover the enormous variation between what we know about objects and what we see.

Learning to draw requires a re-evaluation of visual experience, becoming mainly dependent upon visual cues about the appearances of objects and their relationships in space.  You must draw upon your knowledge of seeing and use devices that come only from seeing. 

Working with such concepts as overlapping forms, diminishing sizes and layered space all require standard techniques which are matters of observation and use of perspective and foreshortening techniques.

To see foreshortened geometric forms you can place a book in front of you shortly below eye level.  Study the appearance carefully then try to draw it in simple outline.  Some individuals may find it difficult to represent the lengthened rectangle of the page of a non-rectangular shape.  Most beginners will draw something that is what the know the book looks like from a different perspective, because they normally see it in a different orientation.

Use your pencil as a measuring device and practice drawing simple rectangular objects in different positions.  For example try drawing a straight chair, remembering to draw what you see, not what you know is there.

You can also develop your ability to draw what you see by drawing blindfolded, and using only your sense of touch.  Explore an object with your fingers and then transfer the image onto the sheet of paper.  By performing this with various objects, you begin to rely on what is, instead of what is in your mind's eye.