Any human in your shot will most likely require special consideration. We expect such human characteristics as gender, age, mood, social status etc to be clearly marked by different color, texture and lighting values, yet the camera, without assistance, often renders them all equal. Skin and eyes in particular will usually require your attention and this might necessitate some manner of masking.
The girls face below was treated by blurring the face but masking the features back in. This is a common technique.
The mans face below tells another story. The focus has been reversed, with the face being made the centre of focus and the background being forced into de-focus. The full file is available in the assets page.
Do you want to learn how to draw the human figure? Yes? Really? Well... the best way is (usually) not by drawing from the real human figure (aka life drawing) or from photos thereof, but from other peoples drawings and paintings of figures. Why? A human pose is a thing that is subject to language.