With all respect to the folks who like random scrappies, I place each piece intentionally. No paper bag. I agree with the ideas
color balance
either one color family per block or common color in one place
value (light/dark) balance

Sometimes I center on a theme, like center animal print

When I have the blocks made, DH and I move them around on a bed until the layout looks good to us.

Each day I learn so much on this board. I love the Pulsar quilt, thanks so much for sharing how it was planned. I love scrappy quilts and have been planning to create one soon. The suggestions made I have copied for future reference.

I agree with other comments. I separate scraps into color bins.