Oh, I so TOTALLY understand.
It has helped me to make mystery quilts. With those, the instructions don't give colour, but things like "1/2 yard of dark, 1/2 of medium to match and 1/2 medium accent". That way, you aren't stuck looking at a picture and unable to visualize the quilt any way except in those colours.
I have also found that the more quilts I look at, the more sure of myself I become simply by identifying what appeals to me, what catches my eye, and what colours I am drawn to. I've been lucky to have had boxes of old quilting magazines handed down to me, and they are valuable sources of quilt browsing.
I've made some random blocks, just trying out techniques and colour combinations. They will always be orphans, but have taught me things!