I would take a hacksaw and saw through a little less then half the pin stack. then put a piece of glass or plastic infront of it.
that is how i have done it, but when you start learning i dont recommend this, as above i would take the lock apart and move the lock down to 2 pins then up to 3...4...5, then your done and can pick pin tumblers.
by the way *use a deadbolt NOT a door knob lock.* i made this mistake and deadbolts work ten times better.
Good Luck!
-Zack