Nothing is required. A birthday party is what you make of it. It will be just as special for your child to have a gathering of immediate family singing "Happy Birthday to you" as a party filled with balloons, ponies, and a catered meal. Do whatever you want to do.
Can you be more specific? Like others have said, a party is however you make of it. I'm big on party planning so how I plan my party would be absolutely different from how one of my friends, who hates party planning, would do her kid's party.
Re: 1st Birthday Party Idea