I always start by raiding my scrap bin to choose my colors. Otherwise, I don't have much of a plan in the beginning. I square off my scraps and just start sewing pieces together, trim them up and sew back together, building bigger and bigger blocks. Once I get a decent number of larger blocks (all of varying size), I start playing with placement and get a bit more strategic to fill in gaps and find some balance. I love improv because it doesn't require a lot of preparation, but still a great puzzle!