To create the perfect party, there are few things you should keep in mind. As a princess I've been to my fair share of parties. Most are amazing, but here are some things I think could benefit everyone!
1) Surprise the princess, or send out an invitation! You can tell the birthday girl you're sending an invitation to the castle to give lots of excitement and anticipation, or you can make it a COMPLETE surprise! Videotape her reaction!!
2) If there are many other adults present, be sure there is a designated "kids" area. Many times if the adults in the area are too loud, it makes it much harder for the princess to interact with the kids and tell stories, ect.
3) If there is a DJ, make sure he knows the plan! There should be at least one quiet time where the princess can speak (and not yell) to the birthday girl and share her story. Perhaps the DJ can even announce the princesses arrival and a sing-a-long intermission!]
4) Be sure all the other guests are aware of our special guests arrival! Ensuring everyone shows up on time ensures everything will go a lot more smoothly, especially if the princess is on the clock and has other bookings!
5) Keep the princess in communication when it comes to planning. Let her know any details that you can to make it extra special! Examples are other favorite princesses, favorite songs, hobbies, her age, siblings, ect.
6) If there are other older kids present who are non-believers, be sure to speak with them beforehand to ensure they don't show off their smartness by yelling, "she's not real! She's a phony!" Yes this has happened and it's NOT fun. Very good older one, you've figured it out, no need to ruin it for the little ones!
7) RELAX and have fun! Let the princess handle the munchkins!