I also use a digital camera to help when I'm putting the blocks together on my design board. If the design is one where I am playing with which way I want to set up the blocks, I'll take pictures of each set up and then review the pictures when my mind is fresh.
When I was making my daughter's quilt, I use EQ5. I had a lot of the same blocks in about 6 different colors. It took a lot to figure out how to set the blocks so that the same colors were not too close to each other. After I finally had it figured out, I printed the quilt out and pinned it up on the design board so that I could refer to it whenever I needed to do so.