After spending an hour watching, I felt regret because I got a headache from all the quarrels. But when we look on the bright side, observing how they talk, I can learn some rhetoric techniques like how to respond to personal attacks and use literature to connect with the audience.
Trump:
Interruption strategy: overrides the opponent while giving a presentation, eliminating the opponent's expression, and increasing his voice's power.
Personal attacks: This is very effective in taking down the opponent. If the opponent falls into a trap and considers it's personal, the opponent will lose points in front of the viewer when showing anger and losing control.
Biden:
Smile: When your opponent attacks you, smile to ease your attack, and show that you don't consider it personal. A journalist from Nytimes commented: Biden laughed when Trump personally attacked while Hilary Clinton did not!
Understand viewers: In this debate, Trump only looks at opponents, while Biden looked at viewers and conveyed his message. I consider this as Biden's success because building an image that Biden cares about people. After all, this debate is about discussing citizen's problems rather than dividing and defeating the opponent.
Using a literary device to persuade: Biden repeatedly used literary methods to make his rhetoric connect more deeply with listeners. For example: "Close your eyes and think about how many empty chairs in your dining table. How many relatives have died because of COVID."
Source: Nytimes