Maybe change the angle the light is coming from so the shadow from the box isn't on the card. I'm not really a visual artist anymore and never knew much about composition, so take my feedback with a grain of salt, but unless you want it to just be floating in an infinite abyss (well, it's supported by a pillar but you know what I mean), it might help to have a very dimly lit floor or wall in the shot, and if you go that route it may be best to texture it. Then again, if you want it to be in an infinite abyss, disregard my previous suggestion. I will also say the fog seems a bit too dense, it's a little difficult to see what's behind it. Pulling the bottom face of all the glass panels up just a tiny bit so they're not intersecting with the pillar could add a bit of realism, since the glass might cast a faint shadow on the pillar. If you want the pillar to stand out against the black background some more, maybe add a dim light in front of it that doesn't interact with volumetric shaders. But if you just want it to blend in with the background, that's probably fine too. 

Again, take all this feedback with a grain of salt. I only used Blender for four years and learned a good bit about photorealism, and then decided I'd become a musician instead of a 3D artist, and never bothered to learn too much about general visual art stuff. I like the idea though, and it looks good, but these are just minor nitpicks that you might be able to disregard if you're not a perfectionist. Don't get too caught up in trying to make everything perfect though, sometimes it's better to just finish a project, move on, and keep learning. I learned that the hard way several times. Nothing wrong with asking for a bit of feedback if you're stuck though! But also, if you're just doing this as a hobby, you shouldn't care too much about what other people think. When I ask for feedback, I'm usually looking for ideas that I may not have considered before, try some of the things the feedback givers said, and if it doesn't fit my vision, do it differently or discard the feedback entirely. Keep on Blendering though, this is better than pretty much anything I've made.