First of all draw a circle.
Now draw these lines it'll help you to locate the area to draw eyes, nose, ear and mouth.
Now start drawing Zack's face beneath the circle.
Now draw his eyes. He has small and sharp eyes like most of the anime character.
Now draw his nose and mouth at the end of circle.
Now draw his neck by drawing these two lines beneath the face.
Now draw his clothes and rest of the body draw his hoodie above the circle. As you can see in the picture above.