Nice space! I think the trend of ginormous clocks has kinda run its course, and while I rail against those who say the dining room is no place for a mirror, I DO tend to think that the dining room is actually no place for a clock, as it should be one of the home's spaces here one is inclined to linger without thought to time flying. I don't think you really need to do anything above the server, but if it were mine I might test a large-ish painting (no glass to avoid glare) leaning up there. I've done that in my own dining space and like the addition of a piece of art at that height. Then again, I'm sort of an art fanatic, and look for any opportunity to display the pieces I love.

I would paint the ceiling and walls a white. Behr Blank Canvas is a great neutral greatbigcanvas.com is a great source for affordable wall art. ruggable.com for area rugs. Navy is a timeless accent color that accespts all colors... mix up textures and patterns as long as they are in the same family.

Yes, remove the shelves and hang art over the sideboard flanked by two matching table lamps with whtie shades and bright bulbs. The tall chair is a bit much in this small space and either chair is a lot of spindles in here. Look for something simpler.

Do you mean the large wall above the buffet? IMO take those shelves away and find a large piece of rt for above the buffet . I am not sure about your style but usually that style of table lends itself to almost any chair style but to me MCM chairs would be a gret choice and maybe even in a color I might get a really large piece of art for that wall and move the buffet over to the other wall where the stuff is beside the door and add another piece of art . But I need a bit more info as to your style. I went to your idea books and the chairs in the 2nd pic there would be perfect with that table for sure , You need an awesome chandelier too and as for a rug IMO get the art first and the chairs then decide the rug.