You got the anatomy down, everything is in its place. The darks and lights can be just as important of course when you're trying to define features, so I would advise you to be careful with your dark/light placement. I would recommend you look into chiaroscuro, which translates as 'light to dark' and a way you can practice, even with digital pencils, is to play around with the eraser tool and set it to a low hardness setting so then as you color in the most darkest parts, you make lighter tones with the eraser!
Nicklost25