Nice room. Your candlesticks and clock seem to disappear there. How deep is your brick mantel?

Love the color of your sofa. It's a comfy looking room.

I think your art could be quite a bit bigger...it's going to be dwarfed by the windows. Try putting the picture that's over the sofa up there (not to leave it there, just to see how a larger piece would look). I think you may even have to go a bit larger than that and I think something with a light mat would stand out against the brick better. That's where I'd start, then pick your mantel decor from there.

I think the biggest result for the smallest effort would be to lighten the matt on the painting -- suddenly it doesn't look too small any more, for one thing. You might consider lowering it a bit so that the top of the clock just protrudes into the frame area.

I think you need to balance out the wall with some dark plantation shutters on the windows. Or at least paint the window trim much darker. The white window trim stands out too much. Your art could be a little bit larger as well. I would love to see the brick whitewashed.

Paint the brick white. Let it recede into the room. Those blinds would look nice with the painted brick. It will make the room seem bigger and brighter, too.