I have done one or two and especially for the last one, I was on a strict time limit on doing it, I would take a picture and them print it out (like you said that you noticed things that needed to be moved) and see what stands out, It is really hard to step back to take a look at, it is not mobile at all when it is laid out. Try to get as straight on shot as you can (I print out full sheet picture on my laserjet and just use regular paper.) and then you can take a look at it that way, and continue the same way until you are happy, you can still take breaks doing it this was as well. come back ever so often to take another picture and look.