When beginning the journey of drawing hair, it's easy to get caught up in the fine details, like the strands, and lose sight of the bigger picture. This approach, however, can often lead to a result that's flat and lacking in depth. As the saying goes, "Don't miss the forest for the trees".
This concept rings particularly true when sketching hair. Rather than concentrating on individual strands, it's far more effective to focus on the larger shapes and volumes that those strands create. By doing so, we capture the essence of hair as a whole, maintaining its volume and depth, and creating a more realistic representation.
Draw with master of likeness Justin Maas here.