Drawing realistic hair can be a challenging task, but with the right techniques and practice, it can be achieved successfully. Starting with the "do's", it is important to observe the direction and flow of the hair, creating layers and texture. Using light and dark shades to add depth and highlights is also necessary. As for the "don'ts", avoid outlining every single strand of hair, as it will create an unnatural look. Overblending should also be avoided, as it can lead to a flat appearance.