Irricca,,,do you happen to have any artwork you could hang? I'm thinking something w/the blues you like would give you a nice change. If you like the clock, it's fine. but the fake flowers in the vases on either side, no. Sorry. you asked for advice. the flower vases just do not belong. (BTW, is that sign picture actually centered on the wall? looks like it's off to one side)
I would do the artwork where you have your sign. You're saying 'something is missing'. some color/art/pattern,,,,that's what's missing. You can find inexpensive art all around. You can make your own for the price of a canvas. (Hobby Lobby, get the 40% off coupon). use left over paint or buy a few acrylic bottles for a few bucks. paint your own abstract. not hard.
https://www.pinterest.com/pin/228065168604188602/?lp=true
Just an example for you to see
Paint your vintage tables white.
get a few of those soft ottomans in a print/color you like to fill the gaping hole in the middle of the room.
you don't need a lot of cash to do these things. and always check Craigslist. tables, art, paint, canvas, etc,,,I've found all sorts of great deals that I've used over the years.
You're asking what's missing, and we are all telling you. All the advice you've been given is good, decent advice. I'm sorry we don't have advice that you can use that is free! sometimes it's just not that easy and you need to spend a few bucks or get really handy. Or, live with what you have!
Q