How to talk fast but clearly?

[Cealey]

For my debate team we have to speak faster in order to get more words in but whenever I talk fast I always jumble my words. I can only practice some speeches because others we don't what our topic is until right before the debate. How can I get better at talking fast without jumbling what I'm saying. I don't have any speech problems I just need to be able to speak clearly and be understood while talking fast. And by fast, I mean like how fast they talk on the show "Gilmore Girls". What can I use to practice? Thanks