After I wrote list of the words associated with quiet, I've marked few words and made abstract illustration based on those words (sea, moon, sleeping, night, early morning). I've tried to unite those words in my illustration. Main idea is sleeping (dreaming) is quiet and calm, another abstract reality that has no sounds. Sea when calm making me think about peace and quiet. In this illustration we have dream about the sea.

I made few variations of color palette and slightly different compositions. First one appeared to me little bit overloaded by details, so I made another illustration lighter.

Quiet:

silence
solitude 
waiting
morning
night
sleep
static 
peaceful
sea 
emptiness 
fog 
meditation
moon