C&C per req:
A nice first attempt, but I see a couple of areas that could be improved. First, always avoid having things 'grow' out of the back of your subjects head such as these bushes. This isn't such an extreme case as say, having a telephone pole immediately behind the subject, but it is a little distracting. Next, unless we can see what's so interesting, it's usually best to have the subject look toward the camera (This is a point on which fashion and portraiture disagree, so if you were going for a 'fashion' look, ignore this). Not necessarily right at it, but toward it, and lastly lighting needs a little work. I'm guessing you used on-camera flash for a fill? Better than nothing but only just. I think a simple reflector to camera left (note the dark shadows on his shirt on his right side) would have been all that was needed.
On a technical note, why shoot this at 1/200 @ f10? Using your long glass and a larger aperture, you could have rendered a nice, softly focused and less distracting background.
Just my $00.02 worth - your mileage may vary
~John