First this one from Medium. TL;DR, Clinton was immensely flawed as a candiate and had Sanders been the nominee he would have beaten Trump. I think this is spot on for the reasons the author gives. The treatment of Sanders by the Democratic party drove people away from Clinton and made it harder for them to eventually support her.
https://medium.com/@trentlapinski/dear-democrats-read-this-if-you-do-not-understand-why-trump-won-5a0cdb13c597#.csfmemtzf Next, this one about Trump and his embrace of the GLBT community. Trump appears to really not care about social issues very much which should make people who constantly harp on conservatives to stop promoting social conservsatism so much. Time will tell how that works out.
http://www.nytimes.com/2016/04/23/us/politics/donald-trump-gay-rights.html?_r=0 Lastly this article from the Guardian that makes the comparisons to the Brexit suprise on the same grounds.