Triangles have always been a challenge for me. Yesterday I finally tried starching my fabric. It makes all the difference in the world! I've ended up with a couple of practice blocks that look really good. The patches weren't wonky and the points aren't cut off. Easy to finger press too saving a trip to the ironing board. Plus they just look good after they're finished - nice and crisp.
This opens up a whole new world of possibilities for me. Thanks to everyone here who suggested starch. I only wish I'd found this tip sooner.