I fell in love with these Ballard Designs Bowen Curtain panels, which are on sale this weekend. They were over my current budget though. I already had 2 pairs of Ritva Curtain Panels from Ikea, so we laid them out in the hallway and marked off every 8 inches. Then we used painters tape to create very thin stripes. We eyeballed the thin stripes and just ensured they were straight.