Pasting protectors need skills

Had purchased a new ipad2 from Supura. It came with a free screen protector. Just wonder how do people do the screen pasting on their own? Ever tried to paste but you see all the bubbles underneath? Every time you tried to remove the bubbles, more will appear. So how did those people who does screen pasting at the shop did it? I saw them just aim correct on the screen and release the protector on the screen and it lay down nicely. Guess even a simple pasting requires skills and practice. I will have to take mine to one of them for re-pasting....