How do you invite your crush to your party?

Try to relax and find a way to take the edge off (go dancing, indulge in some delicious cake, if you are of age a drink or the like, whatever is your comfort, within prudence). Walk yourself, if need be, through the mental process that you can at this point be no less in a relationship with your crush, then approach him/her and attempt to make conversation. Start with something small and light (favourite TV shows, books, movies, the weather, local news, the like) and see how it goes, then branch out from there. If you like what you find, and your crush seems to feel that way as well, take steps to contact later on ('Are you on Facebook?' 'I've enjoyed talking so much, could I get your number so we can do this again sometime?' 'I'd love to email or chat with you again' etc), and part with a smile and possibilities. You just need to realize there is nothing to be afraid of, you have nothing to lose, and just take the plunge.