Ewen MacAskill

Obama: He has to do three things. First, he needs to hammer Romney in the areas he is vulnerable, such as the secret video in which he dismissed 47% of the population as freeloaders, and Romney's plans on taxation and reducing the deficit, which Romney repeatedly dodges when asked for specifics. Second, he needs to defend his first term, being unapologetic about reforms such as healthcare. Lastly, he needs to offer some indication of what he would use a second four years in office to achieve, beyond seeing his healthcare reform programme introduced.

Romney: He needs a repeat of his Denver performance: aggressive, confident and looking presidential. He needs to add to the more human, personal touches. Above all else though, he needs a message, a reason for people to vote for him other than the fact that he is not Barack Obama. The closest he has come to a message is that, as a former businessman, he understands the economy and job creation better than Obama. His team keep promising he will provide 'specifics' of what he would do as president but he has yet to do so, and time is running out.

Ana Marie Cox

Obama: Needs to drink a Red Bull, preferably without mentioning that it was, in fact, a Red Bull on camera. Though if he sky-dove onto the stage, I think that could score some points. More seriously: hammer home just how much the middle class, poor, students, and women will suffer under a Romney administration.

Romney: Needs to continue lie smoothly and frequently, remember to upload his latest HumanEmotionSimulacra™ software. More seriously: Libya, Libya, Libya – it's the administration's most serious screw-up of the cycle, at least its most obvious and public one. Not that Romney has the foreign policy chops to really take the president to the mat on this, but it's a real issue and real weakness. Most likely he'll just talk about the deficit.

Gary Younge

Obama: He must not try to compensate for his previous performance by showing extra aggression. What's done is done, that's not who he is and authenticity beats aggression. Finally, in a town hall format, it'll go down badly. He needs to be engaged not enraged. He should focus on people's questions and skewer Romney sparingly and thoroughly. Debates are a performance and tonight his goal should be to bring out the contrast between their personalities and contradictions in Romney's policies. He must be himself – only more so.

Romney: Needs to recreate that animated version of himself that appeared in Denver while somehow parrying the inevitable charge that he talks out of both sides of his mouth. He also needs to use the town hall set up to emphasise whatever empathetic, human qualities he has. People still don't like him that much and have trouble to relating to him. As such tonight holds the risk of reminding viewers won over by his performance in Denver why it took so long to come around

Richard Adams

Obama: The best advice for Barack Obama is what not to do. Specifically: don't be Al Gore of 2000, who overcompensated for his lackluster performance by upping the tempo in the subsequent debates. The nadir came in the third debate, when Gore lurched over to stand uncomfortably close to his rival. Bush looked at Gore like he was a weirdo and got a laugh from the audience. Whereupon Gore uttered the immortal phrase: "But what about the Dingle-Norwood bill?" If you're going to get heavy on your opponent, at least make it for something meaningful.

Romney:While it's tempting to offer advice to Mitt Romney that includes "Why not bring along a good book to read during quiet moments in the debate?" the reality is that the immediate pressure is off him on Tuesday night. If the punches being telegraphed by the Obama campaign are accurate – that Obama will raise the 47% line and so on – then Romney's best bet to build on his last debate performance is to be relaxed and ready to parry the inevitable counter-attacks, especially the Clinton-inspired "Here's old moderate Mitt" line.

Paul Harris:

Paul Harris byline

Obama: Obama can hardly do worse than last time. That, perversely, will be an advantage in this debate. Both the media chattering classes and Democratic voters are looking for Obama to show some spirit, defend his record and – most importantly – attack Romney. Any move in those directions will thus be seen as an improvement on his last performance. So Obama's task should be easy. He should at least draw the debate. But how does he win it? He has to tread some of the same path as Joe Biden but without the posturing and aggression. He has to firmly rebut and dissect Romney's arguments, but without coming across as a brawler. In some ways that suits Obama's temperament But it is not an easy task. Thus my prediction overall – a draw.

Romney: This time around, Romney has a tough task. Debates are all about expectations and, unlike in Denver, the new rejuvenated version of Romney (Mitt 2.0) is coming into this debate perceived as a dominant force. So he has to up his game, come across as forceful and dynamic, respectful of the president but also aggressive in his grilling of Obama's record. At the same time, he must push a positive vision and reveal himself to be warm, human and capable of reaching out to ordinary, struggling voters. This is going to be difficult given that Obama is likely to go for his throat. There is chance the words "47%" are not going to be flung at him this time.