When working under the eyes, have your model look upwards - only with the eyes, without moving the head.
If you work above the eyes (eyelid), have your model close his/her eyes in a relaxed manner. Children are inclined to shut their eyes tight. Then you can say: keep your eyes closed as if you are sleeping.
Colour the entire tip of the nose and nostrils with a dark colour. Draw a line down from the middle of the nose (between the nostrils) to the upper lip. This line gets wider as you get towards the upper lip and you then draw it along the upper lip to the corners of the mouth.