Step 2: How to make the pattern!
First, fold your fabric lengthwise in half, right sides together. Press it well on the highest setting (steaming would be good) so you get all the wrinkles out and develop a nice crisp line at the fold.
Take your favorite hoodie and turn it inside out and make the hood as flat as possible along the middle fold. Place the opening of the hood straight along the fold a couple of inches away from the edge.
You'll want to trace a half inch away from the hood all the way around it, until you hit shoulder area.
Now, you'll want to trace a couple inches down from the bottom hood seam, and begin taking your line horizontally back to the fold. Make sure to keep this straight!
Based on how thick you want the scarf to be, you'll draw the next vertical line. I drew my line eight inches away from the fold because I wanted a nice thick scarf. I made my scarf 36 inches long so that it had plenty of wrapping length. :D
The pictures explain this so much better.