Also, the rug in the room has some green in it

What about adding a new diffrent color?

Then match it with the pillows and accessories especially in the corners. I think the room would come to live after that.

http://houzz.com/photos/1814146

I'm guessing that you like neutrals and the room has a very calm feeling to it. I think pops of color would really tie it together, but they don't have to be so bright that they take away the serenity. Hard to see the green in rug from photo, but maybe a fern green would be a good accent color. Bright moss? Or another shade of green, but not too dark. Seems to me like turquoise or salmon could be other colors to consider instead of green. Put some accents on your shelves, mantel, another throw pillow, added to the vase arrangement ... For the curtains, you could even just go with a crisp white, or whatever color white matches your mantel trim, and have them lighten up the room even if they don't introduce a new color. For proportions, just from the angle we see the room, it seems like the side table would be better beside the couch arm and further towards the wall, while the vase and dried flower arrangement could be displayed in corner of wall and mantel (since it is shorter than table and sort of hidden back there).

I like the wall color, the sofa and the rug with the rest of your room - The grey drapes and grey and white toss cushions look like an afterthought to incorporate grey into the room.
Drapery panels on both sides of window (keep sheers) that incorporate grey, brown and ivory would tie it all together. Then incorporate the colors from the drapes into your cushions
Here are a couple of drapery panels that would marry all your pieces together (both from Etsy).
The first drape sample would look fabulous with solid green, grey and ivory cushions. (the stripe cushions would look good too)
The second drape sample would work well with tan and grey cushions in a subtle stripe.
(Cushions also from Etsy)

maybe introduce a warmer neutral in curtains, soft gold? Are your floors natural/honey? gold would look good I think...
http://www.jcpenney.com/windows/royal-velvet-supreme-pinch-pleatback-tab-lined-curtain-panel/prod.jump?ppId=pp5003970042&searchTerm=curtain+panel&catId=SearchResults&_dyncharset=UTF-8&colorizedImg=DP0430201405144531M.tif

Here is an update, still need to add the cushions...

...

Not sure about your curtains, I think they are not bold enough, room seems a bit bland, I like neutral too but you have to add a bit of boldness to make it pop, bit like last photo, horizontal curtains look smart to give room lift, add cushions and a throw with some green, lovely space

You have nice, soothing color choices. I liked the curtains that you had In the original photo which brought in the cream color. I did not care for the sofa pillows...which I thought would look better in sage green to go with the rug. Were those curtains green or grey?

With the new curtains you could use cream colored or green pillows with texture, such as faux fur, knit, or woven fabrics.