If the screen of your mobile phone /tablet isn’t scratch-resistant, you may consider getting an inexpensive screen protector to safeguard the glass display of your expensive mobile device from scratches and other wear and tear. →
The following YouTube video illustrates a simple trick that will help you attach the screen protector film on any mobile device but without the annoying air bubbles or creases.
Put on the Screen Protector without the Bubbles
All you need is some Scotch tape (any transparent adhesive tape should do), a piece of lint-free cloth (to wipe off the dust) and a credit card (or something similar) for evenly pressing the film and to push away any bubbles and wrinkles.
via Digital Inspiration Technology Blog http://www.labnol.org/gadgets/apply-screen-protector-film/25411/