Early balloting (click here) has already begun in states such as Iowa and Illinois where as soon as the ballots are ready, voting begins.
The majority of votes are cast on Election Day, but, early balloting matters.
Real Clear Politics has the race to close to call. Nate Silver (click here) basically sees it the same way. He states as of today Hillary Clinton has a 45 percent chance of winning the presidency and Donald Trump a 46 percent chance of winning the presidency.
Nate Silver has added new polls to his election model.
The only polling that matters is the one that is completed on Election Day.
I think there is a larger error than stated by the polls. The polls are primarily conducted online and that isolates many voters out of the polling model. If the error is larger than stated that means the electorate will be more heavily Democratic and favor Hillary Clinton.
As with any major election there is no magic formula. "Get out the vote" is the answer.