Your color values are all very close to each other. If you change it to grayscale, you can see it looks like there's a white screen over everything, or a "washed out" look. Mess around with a brightness/contrast filter and you'll see everything pop and come to life.

On the other hand, if you want everything to feel soft and subtle, leave it like it is. But in my opinion, the higher contrast with richer colors and darker shadows would give it "character."

One particular thing you could do without changing the whole thing is to darken the perspective right sides of objects. Darker shadows give things more depth. (Remember to use a slightly cooler hue, too.)

Another thing you can try is adding more highlights/speculars. You've got mid tones, mid shadows, and semi-dark hard shadows (lines) right now so you have some more of the color spectrum you could explore. And you could use multiple colors of hard shadow to illustrate depth or distance.