Checking Gauge

How to check your stitches per inch, the best way to make sure your knits turn out as planned. The sweater I'm wearing in the video is the Central Park Hoodie (not my design): http://www.ravelry.com/patterns/libra... The shawl on the mannequin is my Sexy Shawl pattern: http://www.ravelry.com/patterns/libra...