Your shading and details are like an expert!
But there's something missing in this sketch, what is it?
After thinking a lot what is missing, while gazing at your sketch for sometime, I found that the head is pretty much
bigger than the rest of body!, his chest and waist are looking like of a girl, you need to make a guy's body more
bigger and wider.
But there's no denying that you have absolutely high skills in drawing, just you need to widen up your imagination
more!
Think like your are making a "character's sketch describing his/her personality" with in those curvy
lines and try to make them "alive".
Your artstyle has something that my artstyle really lacks and my artstyle has something that your artstyle lacks, I know the feeling when artworks looks "half".
But keep it up my Friend! I hope that friends of yours, notice your sketch too!
And is it really as "White day" present? :3