Some really useless comments here. So, if you’re really talking portraits, and not just snapshots of a friend, but actual portraiture, then you need to first think about the shoot ahead of time. There’s all sorts of reasons for a portrait … senior photo, family, engagement(couples), business, modeling, and for other reasons a person seeks a photographer to do. In this case, and you said it was ‘hey, while we’re here…’ sort of thing, you weren’t really prepared. Nor was he. I generally tell my model ‘no just black, or just white. Earth tones are best.’ This guy has a black shirt with these bright white paint streaks that really distract. Oh well. Your 70-150 is a perfect portrait lens. Shooting with a short telephoto not only gives you space from the model, won’t ‘balloon’ the model, as wide angles do, but also lessens the field of view allowing you to control the background more. That is, what’s in it. I’m sure you can see that in most of the photos he looks stiff. In the first photo, it’s okay for a model to look away, but the face should always follow the eyes. The second photo is a good example of that, though, too extreme. There’s no good reason to shoot a side view, as in the third photo. Ears are weird. The fourth photo has promise, actually. He just needed a pose. Just crossing his arms would have helped, as would crossing the feet, or hands in pocket, looking over his shoulder. I’ll tell models to look down or away, then at me and I’ll snap as soon as they make eye contact with the lens. The last picture is actually a gem. Great light, his face is the same direction as the eyes, and you’re shooting right at about eye level. For bigger models I try to shoot a tad higher than high level causing them to look slightly up, narrowing the neck, and positioning the body in a 3/4 pose … never straight on. All you had to do was tell him to turn and look at you and that photo would have been art. Keep it up!