It is tricky isn't it.
The pattern I'm using has quite a chunk of one fabric to tie things together, then uses scraps of whites for the lights and medium/dark prints as contrast.
I went through my scraps and sorted them by colour. The drilled down the medium/dark print to ones that are mostly pink/purple/blue, then decided I have more creams than whites so I'm using those. Then I had to find something where I had at least 3/4 yard of the same fabric to bring things together.
I guess we can judge if its been a successful process when I've finished the quilt later in the year!