Starch your fabric and make strips longer than needed and trim them as you go around the block. I also trim the seam allowance after it is sewn to 1/8", don't think an 1/8" seam is easy to sew. make the bigger seam and trim it. and try pressing them open before you trim them. Use a fine thread like Aurifil 50 wt.
I like to make mini quilts. Look up Rhonda on the board, she loves to make minis' and has some great tutorials.
peace