When I got my makeup done for grad/prom (yeeeaars ago...) I got it done at Makeup Forever and I had already gotten my hair done from the salon. The makeup artist put and iredesent purple glitter in my hair to match my dress, it was really pretty, and I think she sprayed airisole hairspray all over my hair, and then dippped a big makeup brush in the glitter and then tapped the brush over my head to have the glitter fall off evenly, it stuck pretty well, but you have to make sure the hair spray is stil a bit wet/tacky when you put the glitter on.
The easiest thing to do if it's glitter your looking for, is to just buy the glitter hair spray in a can. It's super easy to find around Halloween and you cen get it year round at some salons and beauty supply stores and costume stores etc.