I don't think the gradient isn't very good going into your effect on the right hand side. Lengthen that out a little, and you will see a massive improvement. The lighting is good, and remove the squared effect on the guys face.
A bit like Kadaj said, i'd personally remove the squared effect on his face.
Maybe make a part of his hair a little darker, apart from that, great job.
+ was this a project or spur of the moment?