Close elections can be won and lost in the final week depending on which candidate has the stronger finish.
But I hear you cry: Clinton spent more, had bigger names and celebrities supporting the campaign.
Let me explain. Electors want to see a candidate working hard and a campaign that is not complacent. So we need to examine this in several parts:
The Candidate: Donald Trump in the final week was crisscrossing states with four to six appearances a day. Hilary Clinton was making one or two appearances. Trump raised this by mocking Clinton making a speech ‘and then taking a nap’.
Naming your opponent: The cardinal rule is you do not name your opponent, yet the
Clinton campaign did this throughout the campaign including the branded slogan ‘Love Trumps Hate’. Never give your opponent the oxygen of publicity. This gives your opponent a greater focus in electors minds whilst detracting from your campaigns closing messages.
Closing Messages: At the end of the 
campaign you want to relentlessly push a few key messages. Trump really pushed controlling immigration (the wall) and bringing back jobs (reducing business taxes / changing NAFTA). Clintons message was mainly naming her opponent as I covered above.
Creating an urgency to vote: Watching the left wing political pundits in the media and many associated with the Clinton campaign gave the impression that they were going to win, did you hear the constant references to Trumps ‘narrow path’ ‘mountain to climb’. This may have lulled Democrat voters into a false sense of security. Whilst Trump said in his speeches ‘you’ve gotta go vote’ ‘this could be your last chance’.
Focus on the candidate: Clinton had many celebrities supporting her. On the face of this, that sounded good. However it was problematic for two reasons. One the media coverage focused on the celebrities rather than theandidate. Second it detracted from the candidate and the message.
The combination of these factors meant that Trump won against the prevailing expectation in the media and of opinion polls.
