This is my first instructable, so I thought I'd do something simple. Sorry for the lack of any actual photographs; my camera lost its will to live and dove off the table... I hope my crude 'Paint' drawings will suffice.
This may be common knowledge. Feel free to let me know if my instructable is completely worthless. Here we go...
Step 1: Rectangulatin'
You'll need a small rectangle of paper. Size and precision are not important here (you don't even need scissors, just tear it out). 2 inches by 4 inches works well.