Most people, including me, got it wrong but interestingly my low tech prediction based on Ohio was more accurate than all the fancy complex models used by the experts. I think organisations such as FiveThirtyEight missed some of the indicators that pointed to a possible Trump win. In my last post I mentioned Ohio polls which clearly indicated a drop in support for Clinton in the last 10 days or so of the campaign. Florida also shows a similar pattern. These states were important, without them Trump could never have won.
Clinton (blue) and Trump were very close for most of October, but in the last week or so of the campaign there was a clear separation with Clinton's support dropping (the trend is less clear than the Ohio graph).
A number of people are saying that the polls got it wrong but most national polls showed Clinton with a small lead - this was accurate as she did win the popular vote. The problem for Clinton was - you don't win the US presidential election by winning the popular vote, you have to win the electoral college vote.