In drawing almost any object, you need to see it clearly. Whether outside or inside, the light, most often from the sun, will shine upon it from an angle. Depending on where you sit observing the object, you will see part of it reflect the light most brightly. The rest of the object, moving steadily away from the point of maximum sunlight reflection, will appear progressively darker until, in the underside of the object which receives no sunlight, the object will appear quite dark. In addition, if the sun comes in on the top of the object from an angle over your right shoulder, it will also cast a shadow on the table or the ground. This shadow will also appear dark, but perhaps not quite as dark as the underside of the object.
In a sketch, the top of the object on which the object appears brightest, you will see the object as white or at it’s lightest. If the sun is quite bright, the glare may cancel out some of the color at that point on a lightly colored object. From there to the underside of the object you may see a continuum from light gray to a dark and almost black coloration. A good accounting of this range of gray with give significant depth and form to the object in your drawing. Thus, finding the most well lit area of the object and the darkest or least well lit area, and getting a good view and translation in the drawing of the various gradations of darkness (or lightness) in between is critical. The shadow cast by the object is also quite important. Indirectly, it shows both you and the viewer of the final drawing, the shape of the object from the point of view of how it blocks the sunlight that would otherwise, in the absence of the object, fall on the surface. The shadow will also appear distorted and likely partially blocked by your perspective from the front. If the sun is only 30 degrees or so from coming over your right shoulder while you look at the object, you may see only a small portion of the total shadow cast by the object. Thus, the strongly lit area, the darkest areas of the object, the gray variations in between and the shadow cast be the object are key to giving the viewer a convincing perception of the object in your drawing.
Try your hand at drawing a number of objects–some outside, some inside, some with bright sunlight and some perhaps with just sufficient sunlight to see the object clearly. Do a number of sketches with pencil. Apples, onions, pears, rubber balls are all good subjects. Explore contrasts using more or less light with variations in middle grays. When you have identified and sketched out the shadow cast, be certain that it is reasonable in size in relation to where the bright light appears on the object.
In bright light, a high contrast drawing is important. The drawing may indeed become more powerful as the middle grays disappear. Some say that squinting at the object can help you see the really darkest areas as dark.
After doing a number of sketches in pencil draw the same subject, perhaps under nearly the same conditions, using colored pencils. In this case light, bright colors may start and proceed through a range of blended and progressively darker but different colors to the darkest, but not necessarily black unlit underside of the object. If you are drawing an apple and the light is quite bright and directed toward the top of the apple, the colored pencil drawing will look greatly different from the pencil sketch.