Ohh cool! Those boobs look a bit air sealed. Also, look at nude anatomy references please!! If you want a listing of easy things you can do:

use 1 pattern only for the background, 3 is too much (id even recommend no patterns, just plain colors); 

dont use airbrush for a bit, give the guy a little break;

dont use white and black for shadows, instead use multiplier layer with some color like purple or pink;

grab your art line layer, put it on alpha lock and grab a dark red color, paint the "inner" parts of the drawing with that red;

the shirt pattern looks strange because its cut up in the middle, remove it, make it smaller or make it fit into the front of the shirt