Being able to consistently get a remarkable likeness in your face and portrait drawing can be learned. But there is a skill-set that must be acquired. The first is the ability to strike the arabesque, that is the entire outside shape of the head. The arabesque encompasses the overall shape and proportion. From there, one constructs the portrait by fixing the facial proportions and then blocking in the initial tone.
Even at this very early stage the likeness of the sitter will begin to emerge in the portrait drawing.
The next requirement is knowledge-based: to make sense of and convincingly render the features and supporting cast of cheeks, chin, forehead, etc. you must know the underlying anatomy of bone and muscle.
Anatomy plays a crucial role in conveying emotions. There are different muscles actions for joy and for melancholy. It is more than just a smile on the lips.