Andrew Sullivan has them:

What Obama has to do is show how he is the change, how the GOP is determined to block it, and how he needs re-election to get it done. In the first debate, he was so defensive, so determined to protect his record, so eager not to look smug, he let Romney make the arguments for change. And that’s what excited voters. If Obama allows Romney to offer change versus more-of-the-same, he’s toast. Instead he has to remind us that he has changed the direction for America but that he needs more time to change it some more.

To wit:

more infrastructure investment in energy (cleaner carbon and non-carbon), transportation, and education, all designed for future growth; a shared long-term Grand Bargain – in more revenues and less entitlement and defense spending – to get us back on fiscal track; and a preference in all policies for building the middle class. I’d also favor a new policy: commit to break up the biggest banks, as Jon Huntsman suggested in the primaries. If I had my druthers, I’d also eliminate every tax deduction past a certain percentage of income.

It’s harder to represent change when you are the incumbent. But when you’ve been stymied by the House GOP for two years, you have a decent excuse.