Studying how to lie more effectively.
The pollsters were wrong for the simple reason of they already made up their minds who was going to win and then tried to back into their decision.
If there was one thing during the election that surprised me it was Trump didn’t try to go after NY. I think NY was in play the entire cycle. Hillary won by 1.4 million votes, but campaign stops in the 5 boroughs would have closed the gap significantly if not put him over the top.