ABC News.com

A former adviser to President George W. Bush and John McCain's 2008 presidential campaign says the campaigns and their candidates will focus on three things heading into tonight's debate: substance, strategy and style.

Nicolle Wallace, now an ABC News contributor, knows a little something about prepping candidates for debates. She was closely involved with prepping vice presidential nominee Sarah Palin for her debate against future Vice President Joe Biden.

A little bit of stage fright can set in, says Wallace, and candidates know that in 90 minutes they have to accomplish a lot for their campaigns and political futures. To thoroughly prepare candidates on substance, aides come armed with "massive briefing books that are prepared to brief these guys on their own records," says Wallace.

When it comes to strategy, adds Wallace, both candidates will look for ways to go after their opponent.

Style could be the trickier category for which to prepare. Candidates have to look for "the grace points, the humor, you know: How do you leave yourself open for those moments?" says Wallace.

One thing the campaigns seem to be paying less attention to is the importance of fact checkers.

"We used to live and die by FactCheck.org," says Wallace. "This is the first election cycle I've seen where it does not seem to matter much."

That could be good news for both candidates at tonight's debate because both President Obama and Republican presidential nominee Mitt Romney have been known to stretch the truth in ads and on the campaign trail.