Sketching a beautiful girl

Hi everyone, this is my latest art work. It is an art work of a beautiful girl. The beautiful girl here is one on my closest friend her name is chisom. I decided to surprise her with this drawing, she was astounded seeing the sketch I made of her. It was more of a surprise, she hug me so tight and gave me a peck on my cheek. She was so excited seeing the potrait drawing of her. She showed it to her friends, they were also excited too.
I made this sketch with a pencil, a pen and an fBB paper. I started by making a sketch of the the figure first then I started sketching the areas of the face to create depth. Light and dark is what creates form. The areas that are dark where shaded more than places that are lighter therfore creating form.