If you have access to a sewing machine that sports a rolling foot, you are just minutes away from turning a piece of cloth into a scarf. But to give the scarf a more finished look, consider adding fringes to the ends.
Fringes are easiest to make if you cut the fabric so that the warp (the vertical threads when the cloth was manufactured) stays long, and the short end of your rectangle follows the weft (the horizontal threads when the cloth was manufactured). This will be the cut edge, if your fabric has come off a bolt. If you have a piece that doesn't have a un-touched edge, pick at the last thread on each of two perpendicular sides. The one that comes apart more easily is the weft, which is also known as the woof.
Cut a rectangle of your desired size. For an adult scarf with enough room to tie or wrap, a good length is about 7 1/2 feet. The width is up to your design preferences, but remember you are going to loose about an inch to the rolling foot seam. If you are cutting your rectangle from a pristine piece, you may want to cut 1/4 inch or so from the un-touched edge, as the threads are tighter where they turn back on each other.
Hem the long sides of the rectangle, using the rolling foot, but leave the length of each end that you want to make into the fringe un-hemmed. To make the fringe, you simply remove the weft threads. The easiest way to do this is to use the back side of a seam ripper to pull up one thread at a time, and tug it gently out of the fabric with your fingers. When you have removed threads up to the line of your rolled hem, you may choose to tie the exposed threads into a series of knotted tassels, or to leave them as an even layer.
Some fabrics just aren't condusive to making fringes (especially thin, slippery or satiny fabrics, or at the other end of the spectrum, fabrics like suede, boiled wool or felted materials that just don't want to come apart). For those, it may be simpler just to finish off the edge, and sew on a fringe made of a different material.
Spring may be around the corner, but it isn't too late to make a decorative scarf for those chilly nights.
