The details that make the egg becaome a face include hair, eyebrows and the mouth. The hairline is about 1/4th the height from the top. Eyebrows are basically arches over the eyes that start from the nose area and go slightly upwards and outwards. They curl downward following the outside edge of the eye. Have a small mirror handy when practicing faces. Take a look at your own face. Press your finger near your tear duct... don't forget to set your pencil aside first ^__^ You can feel your nose ridge. Trace it up and outward along your eyebrow. This is your brow ridge. Mimic that line on your drawing. Draw the ridge. It's still a guideline not necessarily the hair of the eyebrow, so you should sketch in the whole thing.
Drop lines from the centers of the eyes. These guides determine the width of the mouth.