For me, I find that when trying to match points - either intersecting blocks or seams within a block - pressing seams open helps tremendously. And when pinning, I place a pin straight up/down through the seam on the top, then put that pin through the matching seam on the bottom block. Keep that pin straight and then put pins through both pieces as close to both sides of the up/down pin then remove the center (up/down) pin and sew. But your blocks look great. Practice and enjoy the process. As someone else mentioned, if it's going to make you crazy then rip 'n fix. If not, no one else is going to notice or care.