Seven candidates will be onstage tonight at CNN’s GOP primary debate in New Hampshire. The list includes former Massachusetts Governor Mitt Romney, former Minnesota Governor Tim Pawlenty, former House Speaker Newt Gingrich, ex-Godfather’s Pizza CEO Herman Cain, former Pennsylvania Sen. Rick Santorum, Minnesota Rep. Michele Bachmann and Texas Rep. Ron Paul.

Each candidate will go into tonight’s debate with a check list and a game plan.

Here’s what I think each of them must accomplish in order to call tonight a success …

Mitt Romney is ostensibly the front runner (albeit a weak one). As such, his most important task tonight will be to simply not mess up. Romney is by now an experienced debater (having run for president in 2008) and is known for being disciplined, polished and “on message.” If he survives the night without committing any major gaffes, he can probably consider it a victory. The trouble is, everyone will be gunning for him.

While everyone wants to be the alternative to Mitt Romney,  Tim Pawlenty is presumably the next guy in line. Pawlenty is widely perceived as being both nice and boring. As such, Pawlenty must come out swinging tonight. (He telegraphed this strategy by taking a shot at “Obamneycare” on Fox News Sunday, though he says he probably won’t use the term tonight.) Preserving the status quo doesn’t help Pawlenty, so he needs to shake things up. The problem is that Pawlenty isn’t naturally combative. The real question is whether Pawlenty can execute this strategy without losing his authenticity. I’m not sure.

Newt Gingrich may not have a campaign team left, but he still has a sharp wit and a busload of ideas. To stay alive politically, Gingrich must summon all his talents tonight. The problem is, while he could easily excel in a one-on-one debate format, it will be harder for him to shine when he has to compete for attention with six other candidates. What is more, people already expect Gingrich to be a good debater, so the bar is already high. Will he rise to the occasion?

Last time, I predicted Herman Cain would surprise everyone — and he did. Most observers say he “won” the first debate. Of course, Cain benefited from the fact that few people knew just how charismatic and talented he is. This time around, people may not be as surprised. What is more, last time, Cain didn’t have to compete with Gingrich or Bachmann. It will be tougher for Cain to shine tonight. The expectations are higher, and the competition is fiercer. But I still wouldn’t be surprised to see Cain perform well tonight. If he does, the “Cain Train” keeps on rolling…

Rick Santorum has a lot of work to do if he is to win the nomination. He is haunted by ghosts of a bygone Bush era. It’s hard to pinpoint any one thing Santorum could do tonight that would immediately change his fortunes. He needs to make major headway soon, but if it is to happen, it will likely happen incrementally. A long journey begins one step at a time. Santorum desperately needs his journey to begin tonight.

Michele Bachmann could catch fire, and possibly even win Iowa. But first, she needs to pass the credibility test. Bachmann’s obvious weakness is the perception that she isn’t quite ready for prime time. As such, Bachmann must avoid making any obvious mistakes or gaffes that could feed into the perception that she isn’t a serious presidential candidate. Complicating matters, people already expect Bachmann to be a charismatic and interesting speaker. Bachmann doesn’t need to score any knockouts, she needs to be taken seriously.

Ron Paul has little chance of winning, but he can still use this forum to advance his libertarian-leaning ideas. Arguably, the most important conversation Paul could start would be about America’s foreign policy involvement. If Paul can express his positions eloquently and seriously, he has the chance to influence the perceptions of listeners, and ultimately, to change the debate.