You have to clean off your helmet before you put the mount on. I also waited a little bit before using it. Put the sticky mount on somewhere warm. Let is sit for a while. If its not completely (or almost completely) touching the surface of the helmet, its going to fall off. Hell, I even smacked my head hard on the ground when I tore my ACL last season, the GoPro went flying, the mount stayed on.
Back in 9th grade I discovered my KNUCKLES.
"I thought you had crowbars?"
"LOL crowbars, what is this, 2007?"