As others have said, two colors work well with the log cabin pattern. I have made a pink/blue, by request from my DMIL, cranberry/pink, lt grn/orange-gold. I really like darks and lights, though. You can make whatever you like, whatever looks good to you. I used the Eleanor Burns Log Cabin book. It will tell you how much fabric of each, and it is very quick to make. Strip piecing goes really fast and makes a wonderful quilt. Just make sure your blocks are squared up before putting them together.