Matching thread color with the color of the fabric is a crucial part of hemming a dress. One helpful hint is to choose a swatch of material the color of the dress and use that as a guide when purchasing thread colors. It's possible to hem a dress either with a regular needle and thread or with a sewing machine. The next most important step in how to hem a dress is determining dress length before hemming. Measure the dress length from waist to hem.
1. How To Hem A Dress With a Sewing Machine
If using a machine to hem a dress, simply choose the proper stitch on the selector guide, pop thread into the bobbin and a thread spool where indicated at the top of the sewing machine. Determine how many inches the hem is to be reduced. With the fabric turned inside out, use dressmaker tape or regular straight pins to tape or pin the hem so that a "temporary hem" is created. Slide the material beneath the machine needle and slowly sew 1/8 of an inch from hem edge, using tape or pins as a guide. Don't forget to remove tape and pins.
2. How To Hem A Dress With A Needle And Thread
Thread a needle with thread about 12-18 inches long, depending on width of hem. Hold the short end of the thread and knot the longer end. This is the single thread method. Turn fabric inside out. Repeat procedure with sewing tape or straight pins, aligning them at pre-determined point at which hem will be reduced. Begin sewing from the point of the vertical seam. Insert the needle about 1/8 inches from the end of the edge of the hem to make a single stitch as small as possible. Repeat this around the entire hem. This is basically a basting stitch that is barely visible on the exterior side of the fabric.
Purchase "iron on" sewing tape or glue that is designed specifically for adhering fabric to itself. Just iron on and the dress is hemmed.