Every athlete knows it all comes down to the finish. It's the same with sewing – just not as sweaty. A smooth, beautiful hem makes everything look better and more professional. The simplest of hems is the double-turn hem, which you can use on almost any edge where you want an easy, clean finish.
The first thing to do is determine how big a hem you need to get the finished length you want.
Most people prefer to err on the side of narrow over wide so there's less bulk to the folded fabric and the hem will lay nice and flat. In fact, it's often better to trim your fabric just a bit rather than make a giant hem.
Let's say you have 2" to work with for the bottom of a curtain. First, fold in your raw edge ¾" and press. Then, make another fold 1¼". Your first fold rolls inside the second and you end up with a nice folded edge on both the top and bottom. Press this double fold and stitch down, sewing close to the fold in the fabric.
Perhaps you'd like a narrower option for the edge of a pillow back opening or the bottom of a table cloth. In this case fold under ½" and press. Then fold under an additional 1½" and press. As above, stitch the hem down, sewing close to the fold in the fabric.
Sometimes, you need a tiny hem for something like a napkin edge. In this case, your double-turn should be just ¼" to start and then a second ¼" to finish. This is also called a "rolled hem" and on many machines you have a presser foot called, unusually enough, a Rolled Hem foot to help you do the job. This specialty foot comes standard on many machines, like the Janome models we recommend at Sew4Home, or you can purchase it separately.
Blind hemming is exactly what you think it is: a hem with stitches you barely notice. This a the perfect option when you'd rather not have the "top-stitching" look of the double-turn hems described above. It is a much more elegant solution.
To learn how, read our article How to Make a Blind Hem Stitch.