Method 1: Allowing the steamer to do the work for you, start at the corner and slow pull with your hand as the steam disconnects the film from the window.
Method 2: Using the more efficient ‘Curtain Technique’, start at the two top corners and remove the film until there is one straight horizontal fold running the length of the window with the top half of the film hanging over. Use the already removed film as a ‘curtain’ to trap in the steam. This will pre-steam the remaining film and make it come off easier. Start removing the film from the sides to keep the steam trapped in the center of your curtain until finishing off at the bottom center.