Technique- Value 

When we are looking at any object our eyes see value first, the eyes compares the relationship between light and darkness. The picture above best shows how light to dark reads; to further emphasize this relationship, you can appreciate photos that have a black and white contrast or you can view the following drawings.

A further tip, you need to pay close attention to the shadows that the object cast and its direction.

Instead of using a black pen or pencil for drawing purposes you can use a water colour paint called Burnt Umber and apply the same technique. So have a go, you can do it!