Trump needs to let Biden talk. The longer he talks the more he forgets about where he's going. You see it all the time in friendly interviews where the TV person will finish his thoughts for him. This makes him look the weakest and most feeble and Trump can't be called a bully or mean by being silent.
Then when it's Trumps turn he needs to just very calmly lay out how incompetent Biden is. Biden tried a zinger when he said something about Trump golfing too much. Trump ahould have immediately zinged him about never leaving his basement.
Towards the end last night when talking about election integrity Biden said soldiers had been "voting by ballot" since the Civil War. Obviously he meant "mail" but these are the things Biden conatantly does and Trump needs to lick up on all of these in the next two debates and then very calmly read Bidens idiocy back to him and ask him what he's talking about soldiers "voting by ballot" means. Force him to eat his own words.
Biggest issue IMO is that trump needs to prep. He didnt. He spoke as if this was a rally, as if he was speaking to people in the know, his supporters. When referencing mail in ballots, he mostly said "look whats happening here, in this state". We at TD know whats going on. People on facebook who are undecided dont.
He was also overly aggressive when he didnt need to be and under aggressive when he needed to be assertive. He was called a liar, a clown, and allowed lies like Charlottesville and "you didnt act with coronavirus" to be repeated and nothing. So weird.