Andy Biersack WIP

This is so amazing!!! I don't understand how you do this !! whenever i try doing shading it turns  out really bad and the proportions kick me in the but >.<, is there any tips you can give about how to do this kind of art ( realistic with all the shading) and how do you make the edges so smooth and make everything just blind together perfectly ? whenever i try i use to harsh of an edge and then i can't blend it right >.< it just gets really bad. and sorry if this buggs ya or anything >.< 
thanks in advance ^-^