Hello Elson :), I agree with the advice that Paola gave you but I'd like to say that what has most distracted and confused me while I looked at you drawing was the perspective and I think you should start with that. Concerning materials I slightly disagree because I think that your value are the result of your understanding of light rather than a pencil problem. If you feel comfortable using the material you used for this drawing there is no need to seek magical material. That said, I really like the drawing , and I find the perspective effect really cool xD but if it was unintentional it really mean you should work on that . Hope this help :)

Hi! It's so cool that you share your work, I really like the anatomy of the person, I see that you really captured the moment. On the other hand, the places where I see maybe you need more work is in the perspective, value contrasts, sources of light, and rendering shadows with pencil, maybe what you need is to try different hardness of pencils (4H vs HB vs 6B vs 8B) to see how they can help you to improve the values. I hope this is helpful, as a student myself I can tell you that drawing is something that you need to practice and also learn about theory because they really go hand by hand. Best!