I started by deciding which colours I was going to put in my book and then sorting my scraps in to piles of those colours.
I decided to make each colour page out of a 6″ x 6″ square. Mostly because I have a square ruler that size so it made it easy to square them off.
Keep sewing until your piece gets so large that there's fabric sticking out from every side when being measured. Then you trim it down to a square and it suddenly looks a million times better!
To assemble the book the idea was to sew pages right sides together and flip them over.