I used a piece of wire to get the basic shape, then traced it onto a piece of cardboard and cut it out. That's a lot easier to take to the store and keep in shape than a wire. Just FYI
Do just behind the shoulder where the saddle will sit in the front and one across the middle where your butt will sit.
Here's a site that has some templates if you're interested http://www.horsesaddleshop.com/easy-...mendation.html
That site also has some great saddle fitting examples and other great info.