Good to see you're keeping up with things! I would suggest you work on faces though, I see some issues with your facial proportions, especially in things that seem to be done from memory. Good news is that there are a ton of face pictures available via Google image search if it's something you decide to practice. There are also a lot of good tutorials and books on the subject, although I don't have any handy for linking right now.
The best advice I got with shading is to think of your drawing as consisting of simpler forms smashed together, and then try and shade those forms. So it isn't an arm or a torso, it's a cylinder with some oval lumps or a slightly puffed out rectangular prism. Also practice shading those simple forms in different lightings as part of your fundamentals to get something to build on.