I'd start with a pair of floor lamps, one in each corner.

I know you have enough pillows, but what about replacing a couple in the same green shade as the vase in your artwork? It would really soften the look and make it more cozy. Agree with a rug...with same shades of green perhaps?

As mentioned earlier, a rug would help a great deal. Also, love your idea of a sofa table and two lamps. I'd push the one side of your sofa (with the lounger) closer to the wall. Then, I'd place a small-depth sofa table behind the other side of the sofa, centered on the sofa. Add two lamps on the ends, and place the artwork between the lamps, about 6" above the top of the sofa. Then, add a long, pretty bowl (maybe wood?) on the table, under the artwork.

What color are your curtains? If you don't have an accent color, I love the soft aqua/blue rugs posted by benjes bride - you could pick up those colors in your lamps and new throw, too. Then, add a great container for your plant, and you will notice a big difference.

i just discovered you can do this in Houzz, i was thinking this will make this space look better, i just can figure out if the collage will be large enough to complete this big wall and I cant add just one lamp to this design but hopefully you get a better idea?

I agree that an area rug would really make this space cozy! More lighting and variety in throw pillows would help too. Do you have any favorite colors or recurring colors throughout your home?
I was also thinking a replacement for the coffee table might help. An ottoman with a flat top like this could have a test set on top, which would create a zone for your candle and coasters.
https://www.wayfair.com/furniture/pdp/warehouse-of-tiffany-cairona-shelved-cocktail-ottoman-why2832.html?piid=27724421,27724420

Autocorrect got me in my first post, I meant a tray* set on the ottoman, not a test!

Natalie you still have no color..

Larger artwork over sofa

While I love the serenity of a neutral palette, I think your room could get a boost from some pops of color - maybe brighter pillows mixed in with the light ones or a different throw. I agree that adding a rug adds warmth.

is that a dog bed near the plant? Perhaps you could add a cute framed photo or two of him ( or her) to the coffee table, something that makes the room uniquely yours.

I would scratch the gallery wall idea, they can be messy, and go with a large piece of art just like kulrn suggested. The blue/green palette she showed you is great.