Get your screwdriver and, using the round metal shaft of the screwdriver, rub down the edges of the skate deck as shown in the picture. You want to rub the edges very hard, and at an angle, until the grain of the grip tape is worn off and the grip tape is white along the edges.
Once these edges have been worn down, try holding the outside leftover edge of the grip tape and bend it up and down. We are trying to make that line that you just rubbed in even weaker, so that it will cut easily and straight. Bend the grip tape some more, and if it doesn't feel weak, rub it more with the screwdriver.
