I hate to cut up fabric if I am unsure of the piecing pattern (how the colors are going to turn out).
I found I need to take a picture of the pattern. Print it out. Grab some colored markers (to match color with the main color in the fabrics -tone wise) and color it up.
Do it a couple of ways and you'll see the design you want pop out. Then label which color is what and start cutting.
It really reduces the anxiety level, especially when the cost of the fabric is up there and there isn't enough fabric to make a bunch of mistakes.
Believe me, I've been there!!! One time I purchased enough for a queen quilt for a class at my local LQS - thinking the pattern would work out just fine - got to the first class, got the pattern, and hated it. I spent most of that class just coloring in the pattern until I got what I wanted. I wound up not finishing the quilt and getting rid of most of the material, after making a bunch of mistakes on the cut.