these things are soooo easy, and i love that you can make a million (or 5) in just an hour! i typically hit up the joann fabrics clearance section and purchase a yard per scarf (2 yards can sometimes make 3 of the same scarf, depending on the material used).
1. wrap the material around your neck to get it to the right length and then cut if need be.
2. sew the wrong sides together [length wise]
3. turn it right side out and sew the ends together to form a circle