this. try to pick low curvature areas of your helmet to put stickers and your less likely to get creases. if you do want to do high curvature areas such as the roll off for the back of the head, cut it into horizontal strips and apply then. i have found decals a lot less likely to crease than stickers. also cutting away as much of the white space of the stickers/ unused decal area helps to get it right. if you do end up with air bubbles pop them with a pin and stick down and if your still having problems after this hair dryer it for a little bit and stick it down. im pretty sure i saw another thread on this a while back so i would try using the searchbar as im sure there was more good advice in the other thread.