I would say you have two issues. In my humble opinion I think (for a portrait shot) your composition is your biggest issue in both images. In the first one, I think he was a bit stiff, and not very natural. The second shot you had way too much inappropriate distraction in the back, and it was cropped way too tight. Unless the activity in the background correlates with what you’re trying to achieve, I would keep it as still as possible and keep people, especially with their back turned to you, out of it. This image would have been very different had it had a still background, or an active background that fit the pose of the subject, which was actually very well done. Had you had that, you would not have had to crop so much, and the background would have worked for you instead of against you. Second, in that image particular, fill light would really have helped out both of these. The first one, I can see where some shadow would work, but for the second one, you had way too much shadow on his face.
This would be my two cents,