PLEASE do NOT do a ballet as a precision routine, as a novice you can get away with it, anything beyond that you MUST have a technical routine, Long John is more up to date with the judging book than me but when I judged Ballet was an interpretation of the music, with no technical requirement. Please pick music that can be used for a ballet, do a video search for stuff with SKYDANCE, who had Mark Lummas, Stephen Hoath & Jeanette Lummas, these guys know how to choreograph a routine. They fly team to music with NO calls, all turns are based on the music. Its such a simple idea but an epithany when you experience it.
So dont busk, dont just fly to music - please think about what you are doing, judges and audiences can spot it a mile off.
A for Sailor's question,
For precision, you will generally be given 3 figures to perform. The difficulty is based on your class (I think). Then, after the figures, you will do a freestyle, where, as Play said, your perform a ballet without music.
For Ballet, you will chose a piece of music, put it on a CD, give it to the person who you talk to to register. Then, when it's your turn, you will go out onto the field and fly to your music.
Remember that for both these competitions, you must have a spotter to pick up your kite, and take it in and out of the flying field.