Stereotyping, or recording phenomena within the visual field symbolically instead of representationally, is the primary obstacle standing between you and the ability to accurately draw what is in front of you.
The best examples of stereotyping are found in children’s art: trees are sticks with green circles on top; houses are squares with triangles for roofs; etc. Instead of drawing representationally, most young children draw symbolically:
One of the main benefits of learning to draw realistically is learning to see things as they really are, instead of as you expect them to be. You learn, for example, to not immediately typecast an eye as what you think an eye should look like, but to see it instead as a pattern of lines and values. You draw these lines and values in relation to each other and end up with a much more accurate rendition of an eye than if you had relied on your preconceived idea of “eye”.
Here’s a photograph of my right eye:
The person who draws symbolically will see this eye and will then draw their idea of what an eye should look like:
The person who draws representationally, however, will see a collection of lines and values and will draw each line or value in correct relation to the others:
While representational drawings are often technically more difficult to execute, symbolic drawings can be very powerful, too, so it is not useful to make value judgments about one style versus the other.