I use Dritz glass head pins. They are thin enough not to distort the pinned pieces. I also pull the pin out and do not sew over them if avoidable. Since you should only press a seam, not iron, any pointed iron should work. I press 99% of my seams open. The trick is to set the seam first but ironing it, then before trying to open it with the iron tip, flatten the seam with your finger and finger press it. This allows you to press up and down, not iron the seam.