Decent line work. Looks petty flat, though - but you seem to realize that, re: the highlights.
If you want to improve the dimensionality, it might help to sketch more spherical objects in different light conditions. Marbles, balls, fruit - natural and artificial light; smooth, transparent, textured... The goal would be to get used to how light and shadow dance and reflect on round things.
Don't worry as much about the detail. Focus on shape, light, and shadow.
Eyes are complicated things. Backtrack a little to the fundamentals, and you'll find that your eyes will start to look more natural