Before you send the invites out, give a thought as to whether or not you want a theme party. For younger children, Halloween is theme enough, and often, specific themes may be lost on young children. Just the opportunity to dress up, eat sugar and run around with their friends constitutes a party, so keep the decorations simple and spend your budget on food and activities. But older children may enjoy a theme and the opportunity to plan their costumes accordingly.
A good way to choose a theme is to pick something that piques your child's interest. Does he or she like superheroes? Well, why not put a Halloween twist on it and have a superheroes versus goblins theme. Let guests know there will be a prize for the cleverest costume. Or create a haunted house and decorate each room with spooky Halloween props. You can get other parents involved as some of the characters -- just be sure the spookiness is age appropriate. Kids like to be scared, but you may want to limit the super scary stunts. You never know the temperaments of all of your guests, and you don't want to give them nightmares.