Ask your little one if she prefers a specific theme. She may have a special character she wants to highlight as Hello Kitty or The Powerpuff Girls (Blossom, Buttercup and Bubbles). Then again, she may just want to be a princess. In this case, you may have all the storybook princesses grace your party as Princess Aurora, Princess Cinderella, Princess Jasmine, Princess Pocahontas or Princess Ariel. Altogether, your theme may be 'Disney Princesses'. On the other hand, she may want to have a fairy kingdom birthday celebration complete with wands, wings, and pointed ears.
A young boy would want a party that he can relate to. Some kids party (for boys) ideas include: featuring a specific superhero as Superman, Batman or Spiderman; featuring a TV character as Spongebob Squarepants or Barney; or featuring a fantasy world as a kingdom of knights, an island of pirates or land of cowboys and Indians.