Awkward space. But with some tweaking... Okay. Get rid of the entertainment center. Mount a flat screen TV over the fireplace, which I usually don't care for, but you can conceal it. Or put TV in another room. Put sofa on wall opposite fireplace. Move the patterned chair towards the center of the room, to the left of the sofa in its new spot as you are sitting in it, so you can comfortably watch the TV over the fireplace. Get rid of white chair. Too harsh a contrast with sofa and patterned chair and rug, not enough space. Maybe get a small bamboo chair or two, something light in visual weight and easy to move, for extra seating. I like the rug; I want one just like that for my family room but the contemporary style and colors are not working at all in your space, especially with the patterned chair. The only piece it works with is the brown leather sofa. You need something much more traditional in style. Do you want more colors, or are you happy with the brown tones?

The built-in is beautiful. I have never seen an application like that. Unfortunately, it only accentuates the vault and all that wall with NOTHING. SOOO much wall and really nothing to be done with it. Interesting visual--your clocks, but I think they would make a bigger statement if displayed closer together. To me shelves are for books--mostly so I want to see a few of yours with some books, just because that is expected. The larger couch does appear to be too far away to really watch TV from. What is behind it? Is that a wall? Perhaps moving it in a closer L with the love seat would cozy things up and give you a new space for a games table or sofa table?

I feel like lighting will make a HUGE difference. Usually when people say "busy" I imagine cluttered, but your decor looks intentional and your house looks lived in but not like a completely kitchy mess. I think it's just the light/contrast letting you down. So don't be so hard on yourself! I'm a photographer and the think that always stands out to me in houses that are really beautiful is how much light gives the spaces texture, definition, and brightness. Because you have darker floors and some darker pieces of furniture in some spaces they all kind of blend together and look really heavy even though they aren't packed too tightly. It's super easy to just plug whatever lamps you have into outlets and flip a light switch that turns on some lights on your ceiling and stop there, but I think the big difference between really put together living spaces and those that don't quite feel as polished is often the intentional use and choices of light. Layering lights at different levels, paying attention to task lighting, and being selective with fixtures can really make a huge difference. I've no where near perfected this in our house yet, but the few changes we've made in some rooms have really had a big impact. I think the right lighting in your home can do wonders and really help establish the ambiance you are going for.

jennifer, if you want to do a slat wood wall (there are a lot of tutorials on how to do it. it's mainly 1x1 or 1x2 wood 'sticks' that are 8'-10' tall. you could use fir and stain them. or you could paint them black. or, if you have a bigger budget, get walnut or something similar. walnut you'd only have to oil. it's a red wood. just a medium brown tone that would great w/the floors. if you like a more natural color, look at 1x2 white oak pieces. (any lumber place should have them) a satin oil finish is all you would need. those can also be stained a walnut color. (oak is cheaper than natural walnut this one is actually poplar that they painted. if you're goign to paint, use poplar wood https://brepurposed.porch.com/2020/01/20/diy-wood-slat-walls/ so, you'd paint the wall black, and attatch the slats. this looks like Alder that has been stained a darker walnut stain. here's the lighter stain color. you could also get plywood and rip it to 1" pieces (however, plywood and lumber have skyrocketed this last year. it's ridiculous what a sheet of plywood costs.) https://simplyalignedhome.com/affordable-slat-wall/ I think if you even did the entry niche w/some type of slat or design would look great I'd go all the way down, and prop paint it black, or do the wall in black and do walnut wood pieces. or, I like this too. find a cool black/white/gray piece of art, something more vertical, and hang it. bring in some bright color stools to fit under the marble. bring in a entry way rug that matches or make a cool design and use that as your art element in the niche (I actually made a headboard similar to this one out of scrap wood pieces. came out really cool) over on the dining wall, you could easily do a living plant wall