The score runs the gamut from operatic to Broadway. There are dozens of numbers in the show.
Sing a semi-up show song like I, Don Quixote (from La Mancha), Summertime Love (from Greenwillow also by Loesser) or something. A song that shows your voice, but also that says that you are more than just a nice voice (and a pretty face).
The big song from the show is "Standin' on the Corner (Watching All The Girls Go By)" and also "Joey, Joey, Joey" got sung a lot.
Best is to get the CD (beg, borrow or steal) and give it a listen. The whole show was recorded so you'll end up with the show structure as well.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher