Toner said Romney should pick "three or four thematic points" to communicate to undecided voters what he'd accomplish as president.

Former congressional staffer Ron Bonjean said the moment gives Romney his best opportunity to show voters what makes him tick. "He has to connect with voters and show some humanity and show some emotion," he said.

Romney has caught up with President Obama in a number of national polls, and swing-state polling shows him gaining ground.

Bonjean said Romney should not stray from his focus on the economy.

"It's so tight right now that I don't think he needs to turn anything around — he needs to focus on the great equalizer, which is jobs and the economy," he said.

While some have criticized Romney for lacking specifics, former Rep. Vin Weber (R-Minn.), a Romney adviser, cautioned that he should not get too bogged down in details.

"There is a little bit of a danger in getting too detailed in the final 60 days of the campaign," he said, warning that if Romney starts weighing in on policy minutiae, it could make it harder for him to govern because it will "disqualify options" for compromise.