rendering help?

Ive been working on this one for a few hours and am wondering how i can create more difference in how i render different materials. for example i want the hair, skin, and clothes to have different rendering? possibly?

Cyclops

Hello, I drew Cyclops and I tried making a background that is like flames and things burning but it didn't turn out to well I think

Box rotation

Į am trying to do the box rotation exercise in 2 point perspective. What I am doing wrong? I know I am using too much lines

chess piece

I would like to get feedback of structure of my drawing and shadows which I know are bad.(Btw this was drawn from real life reference not photo) Thank you in advance.

Please help with my cylinders:(

I tried to avoid too many lines. My cylinders looks a bit off… is it very important to get them super realistic to be able to draw characters? What should I aim for……

Feedback on head study

I did some rembert montald study recently and i try to apply what i've learn from that study but i don't know why after learning some new hatching thecnique and did some Skull study i still feel the head is a bit flat, any tips to make the head a bit more 3d??

Untitled

I think the nose looks a little wrong and the other parts have something wrong but I can't seem to put my finger on what exactly is wrong

I'm a beginner

I'm not sure what's wrong with the proportions of the face

citrus reference sheet

something just feels so off about him, maybe its the pose maybe its the proportions i have no idea why he looks so constipated