Making a drawing with just a few pencil strokes isn't magic, it's sketching! Because this exercise is an art of its own. So where and how do you sketch? Here are a few hints...
Try sketching both indoors and outdoors: the play of light is totally different. You'll be better off working on static subjects to begin with. You can move on to subjects in motion after a little practice.
Examples of static subjects: sculptures in a museum or a park, a landscape, a building, somebody sleeping, people at a concert or a theater performance, etc.
Examples of subjects in motion: animals at the zoo or an aquarium, children and joggers in a park, etc.
Here are some rules to follow:
Time yourself. Set yourself a time limit (5 to 10 minutes) per sketch. The time pressure will help you be more efficient and select the most significant information.
Don't push too hard! If a subject doesn't inspire you, try another one. Sketching requires spontaneity to keep your gesture flexible and spontaneous. If you ask yourself too many questions, you risk getting stuck.
Don't limit yourself to just one sketch of your selected subject. Approach it from every angle. By changing positions, you'll spot new details: point of view, light areas, perspective, etc.
Quick and easy, this method consists of just sketching light and dark areas, without drawing contours. It lets you work on contrasts and volumes at the same time.
You have several options for including color in your sketch: