Overall you did fine. But here are a few points to ponder.

Photo 1 - Cute shot, but watch you background. In this shot you have clutter which takes away from the shot. Nice color though and cute pose.

Photo 2 - Again, nice shot but watch your background. Here the bright burned out area is visually distracting. Kudos though for not glare on their glasses.

Photo 3 - First of all the frame does not work well. It may be a matter of taste you say, but it really does not work. I'm assuming this is sepia? With it being a sepia shot it makes the edges, given the frame, look dirty. With sepia shots faded white edges work the best. Second, the posing. His shoulders are drawn up and thus his neck and shoulder are scrunched and look unnatural. Since your subject is a bit full figured this pose really is not a good choice. Finally, there seems to be dirt / stain on the shoulder of his t-shirt. As a portrait photographer you have to watch for those details. However, a zoomed in shot like this is great for portrait photography.

Photo 4 - Watch your background. The bright, burned out, white area on the right is a problem as the eye is drawn to it rather then your subject. Also, that blue thing sticking out dead center. I'm guessing it's part of a blanked? You do have nice expressions though.

Photo 5 - Most of what I said for number 3 applies here. The one thing that really stands out to me is the messed up shirt. That large bunch behind the neck. Good lighting though.

Portrait photography is all about the details, detail, details. Watch background and foreground. Watch clothing ie. wrinkles, straight colors, tucked in wrong, straight button line, strings etc. Jewelry centered and back clasps not showing. Earrings not caught up in hair. Hair in place, nothing sticking out or out of place. Well, you get the idea.