How to choreograph a tap number?

Hey there, I'm performing in a High school production of "Singin' in the Rain," and I'm playing the part of Cosmo Brown, or Donold O'Connor in the movie. Now, I am a general novice at tap dancing, and just have a few lessons under my belt, as well as the person playing Gene Kelley's role of Don Lockwood, but I think that we should be all right within the months that we have left to prepare. But my main question is how to choreograph a tap number such as Fit as a Fiddle and Moses Supposes, for those of you who have seen the film. Our director has no hired choreographer, and wants for us to come up with our own choreography so that we can be better at it. Now, I've actually choreographed other musicals before, but none with tap dancing in it, and I would like to know what I need to do in order to pull off a successful tap number, especially for fast and up-beat songs. What moves are good to incorperate, what should I be aiming for, and ho do I put it all together? Thank you so much.