The best plan if you're his handlers is that you teach him like 10 canned stats that are true (spin is fine, but the numbers have to be damn accurate). Spread out the subjects, and then just try to get him to drag those up every time the topic comes up. Find a good foreign policy one (how much money we give overseas; doesn't matter for what, the number will rile up his base at home). Find a good crime one about minorities or illegal immigrants. Find one about veterans, and throw in some jobs stuff. And then you train him like a dog to constantly refer back to those numbers.
It'll never happen though. This is easy stuff to come up with, and I imagine that Hillary's prep will have included this. I think it's fairly obvious that Trump's best plan is to stand on a small hilltop of topics, so to speak, and so her goal should be to knock him off of it. She'll have to figure out live on stage what topics that he both wants to talk about and somehow keeps avoiding. Then you'll know you've got a subject that he hasn't been coached on well enough (i.e. his handlers will tell him to avoid such a topic).
If she gets him off the cuff, he's done for. His style of speaking is atrocious for anyone not in his camp already; if you're following the reasoning and you're well-versed, then he's blatantly incorrect. If you're not, then he's confusing with his rambling sentences. Low information isn't that bad of a strategy (a la Lois on Family Guy just saying 9/11 over and over again), but you have to at least be coherent. Trump isn't.
