Been trying to make a porftolio, so here to show my stuff
I don't draw much realistic stuff, often opting for cartoony stuff instead. I've been trying to work better with inking, so I hope it is going the way I want to improve.
A very simple sketch of Batman
And a Dragon I drew for someone
Felt nostalgic, therefore I sketched Q*Bert as well
As for specific advice, right now your inking needs a little work in terms of line quality and thickness. On the dragon in particular, the line seems to get thicker pretty much at random. A good rule of thumb is that lines on the outside of a character should be thicker than the lines on the inside. Also thicker lines at curves and corners (elbows, cheekbones, jawlines, stuff like that).
Start to think about light. Light and shadow is one of the most important and fundamental keys to being a good artist. You can create shadow with lines or with tones (markers or something similar). Look at this month's enrichment exercise, it could be helpful in that regard, doubly so because it also focuses on basic shapes.
I hope you keep at it, good luck.