The best way to learn about how to write dialogue effectively, is to go out and observe dialogue in it's natural habitat! Your mission is to go out into the school and eavesdrop in on a conversation. Listen to the conversation for about 10 minutes, record the content and your observations. Make your notes as specific as possible as we will be debriefing as a class upon your return.
Discuss the dialogue that you overhead:
Finished assignment = 350 words. Post it here in the comments, and on your blog.