The standard seam allowance is 5/8 inches. Sew with the material to the left and the seam allowance to the right. There is usually a 5/8 inch mark on the throat plate of the machine. If not, you can make one with a piece of masking tape. Some machines have a screw-in seam guide or you can buy a magnetic one. (Check with your dealer before using a magnetic seam guide to be sure it's ok with your machine. Some machines with metric stitch plates also have an optional one that has inch markings.