How to be a good host of an event?

So there is a ballroom dancing show next week and My teacher picked me to be the host. Which means I have to talk in front of hundreds of students in my high school and in cameras.introduced the dancers etc.. I have acted befor in front of people but never talked in front of hundreds of people. So my real question is what are some good tips to not mess up on what I say and entertained people also how should my personality be and how should I prepared befor the show. I want to sound Professional( like Ryan Seacrest ) but awesome also