How do you say "Hyung, you look so cool!" in hangul? Is it "형 너무 멋져!~"?

Question

Answer

Yes, it is. 
1) Hyung - 형 
2) you - we don't translate it because "you" is "형" 
3) to look - ~처럼 보이다. 
4) so - 너무(positive meaning) 
5) be cool - 멋지다. 

To sum up, 
"형(hyeong), 너무(neo mu) 멋져(meot jyeo)"

Answer

More simple, 형! 짱!

형-  Hyung, means, you Know, Brother
짱 - Zang,  this word is NEW and we used in common, and young people saying this word, 
   I think this word is more closed, meaning of "멋져"