Bubbles belong in the bath, not on the wall. If you see any, pop them with the tip of your utility knife or a pin - then work the air out with your fingers.

A few tips:

• Pop the bubbles before removing the protective film whenever possible.
• Keep the gray pad of the applicator FLAT on the wall while applying and you'll get fewer bubbles.
• When removing the protective film, walk the film down the wall instead of pulling it out straight.