I realized after my last post that not everyone is going to know what princess seaming is. The technique is fairly simple.
With wrong sides facing, so you're sewing on the right side (what will show when you're done), sew your seam with a narrow margin, usually around 1/8". Fold the fabric back so that the right sides are together and then iron the seam flat (it makes the next part sooo much easier!). Sew another seam that hides the raw edges, usually wth a 1/4" margin.