A few ideas are starting to emerge as keepers.
I continue to believe that essentially ignoring so-called social issues, rather than digging in our heels, is the right move. Wanna outlaw abortion? Our position should be something like, "We recognize that abortion presents our society with fundamental questions that should be fully explored. As a party, we believe in upholding the Constitution of the United States, which at this time protects a woman's right to choose."
That's it. Same for gay marriage. School prayer. Let's recognize these issues for the winners they are: either the Republicans get their way and alienate everybody, or the right eventually figures out that the Repubs don't really care about these issues.
The best possible outcome would be for these things to simply fade away from public view, enjoying the obscurity they so richly deserve.
Another tactic: we should pick a few government programs that enjoy broad support, and demand that they be improved and beefed up. Take food inspections: most Americans are reasonably enthusiastic about their tax dollars going to make sure our food supply is safe. But as any viewer of local news shows during sweeps knows, our food supply is far from as safe as it could be. Let's propose a massive increase in the number and thoroughness of food inspections.
It may be that safe food is a loser, but let's picka couple.
The other area I think we should explore consists of issues that make Republicans uncomfortable. Let's get back to talking about our wasteful defense spending. I suspect the Conventional Wisdom is something like, "Oh, no, we'd be seen as weak on terror." But Democrats have made hay for generations by focusing on obvious pork. A riff on this might be to become the anti-pork barrel party, and make that a centerpiece of our message (analagous to smaller government or lower taxes). Of course, that would mean we would have to lay off the pork, but hey, it's pretty good policy, and with our guys on the outs in DC, how much are we really giving up any way?
Two last thoughts: One, we have to put the lie to the various strawmen that Republicans need to survive. So when red-staters voice fears about higher taxes, the question we should be asking is which Democrat raised your taxes to such high levels? Or, which Democrat want to take away your guns? Or force your kids to be gay? Or prevent you from practicing your faith? We're the guys who are tolerant, not the Republicans. In a similar vien, we should stand up and defend forthrightly our own values. The Ivy League is a good thing. East Coast liberals are the guys who favor raising everybody's living standards, and are really good about being caring and selfless.
Finally, we have got to find some leading voices with a Southern accent. This doesn't mean that our PResidential candidate must be a Southerner, but we do have too many New York and California voices. We should be reaching out to bright people from our toughest areas to join the cause, instead of hiring so many from our strength. (We could also look into finding more enterprising ways to tap into young creative talent: right now, there are too few oppportunities to make a career in the politics of helping each other.)