I can’t think of any improvements - you are a great artist, and obviously your talent is well above mind. I’ve had a graphic tablet for many months now, and am still struggling with the basics of pencil and paper! Keep up the good work and look forward to more of your drawings!
Your drawings are quite good, where the highlights and shadows ought to be are captured properly. You might want to practice more on perspective though - it shows through for the Pandora and Female drawings, but otherwise it looks really great!