This is really a good method for opening doors that are locked.  The only setback with this, though, is that it only works for outward opening doors.

This method is preferred over regular lock-picking if the door opens outward, because it is a lot quicker.  Lock picking can take 5 minutes... When done correctly this only takes 30 seconds!  So, if you can, use this.

Learn how to pick an outward opening door with this easy to follow guide.