Like you said, you obviously have a light issue in the room due to the addition of the corner ceiling light and the need for sheers. Maybe paint the ceiling white. Definitely replace sheers with white plantation shutters and add your beautiful chosen pendant lights over the table. As the table is long maybe you can have the light above the window (and if there is a third one further along) moved in to have them over the table. If the pendant is very large have only one or two and remove the extra light/s altogether. You could also possibly add two wall sconces to the wall opposite the windows depending on the overall room. If you physically can't electrically fit lights on the walls now consider battery candles in the glass flutes. This would give lovely mood lighting. Have the white plantation shutters with no additional curtains but have a very large striped rug either the same red as in your photo with creamy beige to blend with lighter wall; or a light blue and white/ creamy beige rug. The light blue stripe would give a relaxed sense to the room. You may need to have these rugs made up. On the table, change to a larger silver tray and look to improving its content holders to silver and glass, light blue china and one low wide rounded fresh flower vase in silver. For dinner, remove your tall vase of roses and replace with a couple of large glass fluted candle holders with silver base rims with pillar candles either side of the tray. Best wishes.

Are you keeping the blue carpet? I would suggest if the carpet is staying to use a band of the dark blue colour on the bottom of the curtain, say around 50 - 60 cm. Then the main body of the curtain to me made from a textured or even self patterned off white or natural oatmeal coloured fabric. (See attached pic) This will marry up the flooring with your walls and the lounge suite.

The photo below is my suggestion for colour of floor. Furniture should be darker - similar to below. For the rug - choose one colour from the artwork and find a similar coloured rug. Don't put a mantle over the fireplace - it could be a health hazard - bumps and bruises. Blinds - unless you want them to make a statement I think white - to match window frames would be fine.

I note you have blinds already.We too have blinds and my light sensitive husband found the cracks of light down the sides woke him early. I stumbled over a place that sold ends of current fabrics at very reasonable costs so bought enough linen to match the wall colour and lined it with blockout lining.I made each curtain 90cm wide although once they are gathered on the 30cm long track they are full and generous looking. (so they only cover the edge of the blind) and have totally cured our light problem for well under NZ$100. We bought a metre of track and two fittings that allowed us to make two 30cm rails, using a hacksaw to cut it down. I too agree, match the wall colour so you have a good plain backdrop for duvets and accessories in the room. I'd be hesitant about a feature wall in a small room,may close the room in.