1: I think the trees and the bright greens interrupt the balance of this shot. A crop would be useful.
2: Looks okay,
3: I would delete this one, it doesn't look like a keeper at all. Too much chroma on his face and there's too much negative white space coming from the left.
4: I think this needs a crop from the right about 25%, to isolate him on the streets more and emphasis his person.
5: I'm not really a fan of this.
6: I'm not a fan of this one either. It feels too much like a snapshot and his expression isn't very compelling.
7: I think the eyes need to be brightened up (got photoshop? Dodge tool works wonders for that). Set it at a low opacity and the mode for "highlights" in the toolbar. Soft circular brush to bring back the irises.
8: I like this one the best