Contrast

Contrast comes many different ways. This one is obviously HIGH contrast. It is sometimes called graphic. When you start adding prints instead of solids it softens the contrast.
If you like to stay with all solids, adding a value that is halfway between the dark one and the light one will give each fabric an almost equal amount of presence.
In these 4 blocks I was playing with LOW contrast. Only the bottom right one really shows the block pattern well; with the others you really have to look for it. Decorators will use low contrast prints in a variety of floral, stripe and geometric so that there is a blend and not one fabric taking over the room. When I make a quilt with lower contrast, I am usually just trying to introduce color into the room but not make the quilt the focal point.
Here are 2 blocks of Night and Noon, one in pastels and one in bolder colors. In the one on the left the fabrics are more "solid color" looking prints whereas the ones on the right are mostly quite busy. You only have to identify the look you like to figure out what kinds of fabrics to buy.
I like the very busy look, so very few of my quilts have tiny prints that almost look solid. I would be more likely to have a light print like the block on the right. I like the way the leaf print star points almost disappear into the background print in places.

Amy said in her comment the other day that she would like to see a post about contrast. I hope this explains my view on it.