Which ocean? If it's the Atlantic, I suggest putting a mirror behind the new leather sofa,
https://www.wayfair.com/decor-pillows/pdp/latitude-run-aristoula-wall-mirror-w003278512.html.
A copper coffee table might be very nice in room.
No matter which ocean you are on I suggest taking every thing off the mantle. I would keep an eye out for 2 nice wood boxes that you can set atop each of the bookcases, because I think something needs to close at least some of the gap to the ceiling. An alternative is to set each of the cases on a sturdy plinth to bring the tops up to just a bit above the window trim.
If you don't need drapes for privacy, just remove those. If you do need them, get longer drapes.
The quirky rocker would look better at the right corner of the fireplace. The green chair can be set at an angle with its back to the door. (The entire rug could be pulled further from the fireplace -- and you appear to have such nice floors I don't think you need such a large rug.)
I hope the grandfather clock can find a spot in another room. Move the drop leaf table from the window to that wall by the door, open up the leaves, and put all your plants on the table and the bigger ones on the floor near it. Put a window seat bench under that window.
It looks like you like to read, so once you've got the sofa and coffee table in place, invest in reading lamps where you need them. With a big enough coffee table you probably don't need end tables, except maybe some light weight drinks tables you can move around.
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Chandelier dining room
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