I hear you! I start by charging a ton

I still end up having to fit it a couple of times. I also prepare the customer that no matter what I do, some little dust specs will show up.
I clean (spray) before I remove the plastic layer. I spray it again after (with plexiglass cleaner) and wipe it down. I make sure the art is as clean and dust free as possible. Then I say a good amount of prayers to the Gods and Goddesses of static (these will be followed by as many curses), take a deep breath and give it a try.
I have heard that those anti-static 'guns' are quite good but I have never used one.
I make sure that the shop is somewhat humid (fitting this stuff is easier in summer humidity than winter freezing).