For all you guys with the luxury of working indoors and out of direct sunlight, here's a trick I developed back in my in-the-shop days during the winter when the pop-ups are at their worst.
I started keeping a 70% water/30% alcohol hand sprayer in my arsenal to aid in adhesion.
70/30 is the best ratio I've found to avoid burning the glue.
After cleaning and wetting the glass normally I spray the 70/30 onto the glass, roll on the film, turn on the defroster, and wait approximately one minute before starting to squeegee(strictly blue max and side swiper for me).
Adjust wait time as needed.
Try it, you'll be amazed at the difference.
Also as an added bonus since the alcohol softens the glue, you will be able to rub in dirt or creases(me?! Never! ) more easily and often without any heat necessary.
Have fun out there!