So the pic above is what you have done so far for your helmet...correct? If no, post a pic, if yes continue: Next order of business is to fill in the seams and get the cut lines cleaned up. A little caulk will do nicely to fill in those gaps. You will need a paintable flavor of caulk....keep that in mind, otherwise the the paint won't stick (Thank you Capt. Obvious for stepping in to the room and announcing yourself). Also invest in a sanding block or sponge. If you really want to go all out, an orbital or table top sander will go a long way to getting smoother ends. Now as far as noty knowing how to cosplay....... have you been to some of the cons lately.......aluminum foil and cardboard is all you need apparently. Maybe some scotch take.....but that is optional.