Step 1: Cutting your graphic onto your vinyl
If you happen to have a vinyl cutter you can just send over your graphic from adobe illustrator.
If you don't happen to be so privileged you can draw out your graphic on your vinyl with a sharpie and then cut gently with an x-acto so the backing stays intact. I use a number 16 but I'm sure the typical 11 would also work.
I got a 10yd roll of white vinyl form signwarehouse.com (http://www.signwarehouse.com/c-VAVA4O1510.html) I'm not an expert in the different types of vinyl but this stuff works for me.