He's got plenty of character.
I think you might want to work on his expression a little. Make him look more like he is into his singing. If there wasn't a mic infront of him, he might appear to be yawning.
Nice job. I look forward to seeing more of him.
Urp
Agreed. More emotion in the eyes. They should squint a little. Also, the corners of the mouth could be drawn back a bit to create creases, which you would see in any singer, whether it's Marvin Gaye or Anthony Kiedis.
Hands can be used to further suggest a singing pose. They can grip the microphone or something. Is this thing going to be animated? A clip would be much more telling than a still.