Lightly tape out the floor for both an 8x8 rug and a 10x10 rug to see which looks best. I think I'd prefer 10x10 but would need to see it.

I'd like wallpaper in here but only if you wallpaper the ceiling too. If you leave the ceiling blank it is going to feel like a milk carton. If not paper, then I'd go for a slightly moodier neutral paint on the rest of the walls and ceiling.

What chairs will you use?

I'd like a wing back chair or tall plant in the corner to the left of the window. I think this will fill out the room nicely, making it cozy and not as crowded as another case good. Get your rug in, artwork hung, paper and window treatments up, then decide what else you need in here.

Others will have better ideas than I on the window treatments.

Congrats on the new buffet. It looks great in here.

I would go with neutral light rug, chairs and curtains

I like the chairs but IMO they should have matched the wall trim better . I think a rug needs to be big enough to have 3' all around the table so bigger if possible so 10x10 would be great but I agree map it out. I would like to see the chandelier hung a bit lower and drpaes and not the window covering you have now they do nothing for the room I would do a permanent custom solar shade for the arched window and drapes hung on a rod just under the arched window A nice slik drap couyld be great and if it matched the trim on the walls even better so maybe you could find a stripe . I usually love round tables but in that space I think a rectangle would be better use of the space and a much longer sideboard too The art will be tricky to hang with that trim maybe with a longer lower sidboard you could do a more horizontal piece . Some lamps on the sidborad for added lighting and IMO keep the chairs. I would for sure not do a neutral rug but a nice silk or Persian one with a bit of the trim color would be awesome

The wainscoting should have been painted white IMO.. Your room details and the chandelier would have than had a great backdrop. The blue you select sucks every bit of light our of the room.

First major decisions are the rug and if adding wallpaper, as they will drive other choices and room’s outcome. Moody with a light rug is where I’d head and if you don’t need privacy during day, drapes left open will provide lots of light.

If you want drama, add wallpaper but if mixing patterns is not your forte, maybe skip or get professional advice, and again light vs dark is another decision.

Decide on the chairs (yours are nice) only after rug and/or wallpaper are decided on. Before purchasing the china cabinet, tape out its dimensions to ensure it won’t feel cramped. You’ve got a lot of decisions and suggest saving lots of inspiration pictures and you’ll start to see what is resonating with you. There are great bones to work with!

I like the chairs you have. Wait until get the rug to decide on the chairs. The rug needs to be a lighter shade than the chairs, if not neutral.