I am new as well, I think you have a good idea and a good start on shading. the only thing I can add at this point is the arm is out of purportion and looks a little stiff. Be patient and give yourself time to use the apps well. It is not the same as having a brush or pen in your hand. There are a lot of people here who's work is fantastic but they have been at it for a while. One persons advice to me was to watch other peoples animation to see how they do their work and welcome