Just as Superhero parties are popular with little boys, princess parties are popular with little girls.
The most simple and effective symbol to incorporate into princess cupcakes is the crown. Even without a vast amount of sugarcraft experience, crowns can be made with little more than a bit of patience. Have a look at these simple but beautiful cupcakes by hollyz1 at Cake Central
Or these piped crowns by Sprinkles Dinkles
It seems when you want to advance from crowns, your designs may have to become a little more intricate and complicated. However, if you are confident to try, see if you can get any inspiration with this great collection of Cinderella cupcakes by Girlie Bubble
Or these cute chunky designs by CuteCupcakes
And if you want to go to whole hog, maybe have a go at actual princesses on cupcakes, these are by Crazy Beautiful Cakes