I think it's key to look at the polls in aggregate, rather than one by one. For example, if you look at the 538 page with all of the available polls included, you see that Clinton is ahead of Trump by almost 10 points in Michigan, for example.
The site Princeton Election Consortium (http://election.princeton.edu/
) is excellent. It's run by an academic, Sam Wang, who is a neuroscientist and does political prognostication on the side.
And browsing through Trump's recent tweets shows his practice of cherry picking individual polls to create a perception of a close race.