1) Make sure your windows are super clean before you but the film on. Nothing more frustrating than having to peel it off once you've got it on perfectly, just to clean off the little fingerprints that you missed. 2) Wet the window with soap and water before putting on the film, this will make it easy to slide the film into the right position. 3) You will have some bubbles in the film after you apply it, and get it in the right spot. I used a rubber spatula to work the bubbles out by pushing them to the edge of the film. A credit card works too, just make sure it has a nice flat edge so you don't scratch the film.