The BBC website recently had an interesting article about the speaking style of president John F Kennedy. The article was to mark the 50th anniversary of his inagural address.
It lists 6 key elements to JFK's style which made it so successful.
2. Three-part lists
3. Contrasts combined with lists
5. Bold imagery
6. Audience analysis
While it may not be possible or practical to apply all of this in your debating style it is worth a read. It certainly may be more applicable if you are writing a prepared speech and have time to develop and build in such elements.