Drawing by copying is useful for beginners. It lest one to practice the style and methods of drawing without being concerned about the exact subject matter. Copying also gives training to the eye by allowing one to correct mistakes in the estimates of lengths. A next type of drawing is perspective or object drawing which gives knowledge of form and construction. The relations and relative sizes of objects to each other are learned through drawing them. There is a most important form of drawing called as imaginary drawing which enable an artist to express thought and impact ideas. Proportion accurate eye measurement is required t draw figures in proper proportion. If the head is drawn twice as long as it should be, the whole figure looks out of proportion because the head seems unnatural. Body sizes should be compared to each other, and made in sizes relative to their proportions. This takes practice, close observation and ability to measure with the eye. An effective exercise for learning to draw relative proportions is to use some ordinary object as a standard measure and draw it carefully. One can simple objects of different shapes and sized. One can get more info about drawing from the trained professionals.
One of the mistakes beginners make is to draw on too small of a scale. In copying pictures from magazines and books the beginner naturally copies it as is, at that size. The beginner usually does not know that the original drawing from which the picture was made almost certainly much larger. Varying the scale of drawings is good practice to keep measurement and proportion skills up. One can use internet to find more info about the various style of drawing followed in different places. The artist can use simple objects they find around them as a model. Draw them singly at first and as they advance group them together. Use objects with dull surfaces. Models with single color are best at first. Placing the object at right background is very important. It is difficult to discern form when there is no contrast.