This is such a nice photograph!
The composition is very strong and you’ve included enough visual information to keep the photograph engaging. You’ve isolated your main object (the dog), but you’ve provided enough secondary context and texture which allows your audience’s eye to explore the backdrop to the photograph as well.
What I like most about the image is the expression of the dog and the composition of the entire image. As a general rule of thumb, eyes are placed in the top 2/3rds of the frame (just like you’ve done). This is also true with human portraits as well. Many photographers place eyes in the center of the frame, but it’s generally less desirable to do that (there are exceptions of course).
You’ve also used a minimalist color palette of gradients of brown and black. This has helped you organize your composition and allowed you to draw your viewer’s attention to only the most important details.
You’re right about the glare on the couch. One way to fix that is to use flags. It’s one thing to know how to light a set, but it’s another to know how to block light. You can pick up 3 feet x 4 feet black pieces of foam core from your local art supply store for about 7 dollars. You should also but metal clams to help you attach them to objects like chairs or tripods. Black foam core (unlike white foam core) will allow you to cut your light so you can control how and where it falls in your composition. In your photograph above, everything else is properly exposed, but I agree that the glare should be toned down just a little bit and a black piece of foam core placed just out of the composition could help you block the light from hitting that area so hard.
I hope this helps!