I think alot of it is practice. I was trying to get all "fancy" with my Boomerang blocks and kept messing them up because the points didn't match. I started doing 9 patch because my LQS teacher told me it is a great way to practice lining up all your seams. Still after making a ton of 9 patches.....sometimes they are perfect....sometimes not. I figure I'll keep practicing. I do know that alot of it is the direction you iron the seams and then put them together....like they should kind of "notch" together.