First, you want to start with a piece of ribbon that is about 3" longer than the piece of cardstock that you are wrapping it around. For this, I used Black Grosgrain ribbon. It is 7" long. Thanks Marla for being a great hand model!
Next, find the mid-point of the ribbon. At this point, wrap it around your finger and tie it in a knot. I will tie a double-knot just to make sure that it doesn't come loose. Please be careful not to tie it so tight that you cut off circulation. You will have a loop in the middle of your ribbon now.
Slip the loop off your finger. Use scissors and cut the loop... and voilà... you've got a bow! Wrap the two ends of the ribbon around your card, secure with adhesive and you're finished.
Here's a finished card using this ribbon:All images ©Stampin' Up 2001-2007