Donald Trump has had an excellent couple of weeks. While Hillary Clinton's e-mail scandal and rumors about bad health continue to plague her campaign, the Republican nominee has been gaffe-free and on message for weeks, and polls are starting to show that his discipline is paying off.

A poll from Franklin Pierce University/Boston Herald, released on Tuesday showed the Republican nominee making large gains among important demographic groups: Independents, millennials, and minorities.

The poll shows Clinton with a slight lead over Trump nationally, 43.7 percent to 41.4, with Libertarian Gary Johnson at 8.4 percent and Green Jill Stein at just 2.6 percent.

Among Independent voters, however, Trump clobbers Clinton with a 14 point lead: 44.6 to 30.2 percent. This is a nine-point gain for the billionaire from where he stood in July, when he and Clinton were within the margin of error among people without a political party.

Trump also closed the gap significantly among young voters. Among older millennials ages 25-to-34, the Republican nominee has an 8 percent deficit a double-digit gain from July, when Clinton led the billionaire by more than 20 points.

Minority voters have also warmed up to the billionaire; Trump received 36 percent of the Latino vote and a whopping 19 percent of the black vote. Back in July, Trump only had 29 percent support among Hispanics and 9 percent of black voters.

If Trump can hold these numbers along with his base of non-college educated whites, he'll be in a healthy place come election day.