One: Cheating. If your trying to impress someone easily have one pre-tied and slip it into your mouth. Put it under your tongue then switch them out while hes/shes not looking. No one will know any better. (As seen on TV baby!)
Not cheating: Break the steam into three sections (About equal). Hold the top half with your teeth and use your tongue to guide the steam to cross over to make a basic circle at the top. Then hold turn it to your molars to hold it with ends out. Choose an end to stick through the top. It takes a few minutes the first time but once you get it, it only takes me seven seconds to do now.