My main suggestion would be to frame the shots so as to give the subject more space within the picture area to look into, rather than having the subject looking into what many of us refer to as "the short side" of the frame. Your last shot is a prime example of placing the subject so that he is looking right OUT of the frame, with his gaze directed at the short side of the frame, with his body placed far off to the right of the center of the frame; this subject placement and line of gaze (those make up two things, subject placement, and line of gaze) causes visual tension. Shots 2,3,4,and 5 all have what most artists would call improper use of the compositional space for traditional portraiture, or for just general picture-making. I mean "improper" in the sense that the subject is placed too far to the short side of the frame, and is creating an off-balance or tensioned feeling to the overall photograph.
I think that from one point of view, you've sought out and found pretty good locations and decent if unspectacular lighting to shoot in. Your dark tones (like his sweatshirt for example) have a bit too much darkness to them, but the colors are mostly pleasing, and each photo conveys at least some sense of the lighting that was present at the time of the session. What you have done is something you might not fully be aware of; you have created a sense of PLACE, and then put the subject in front of that place, in each shot. Although I'm not fond of the manner you placed the subject within the frame, the fact is each shot shows us a lovely autumn "place", a location, a setting, and that's pretty good. Your backgrounds are actually quite good and well-chosen! Definitely, you've chosen the actual shooting locations quite well.
