What was considered fringe interest a mere five years ago is now mainstream. Talk of global warming, alternative fuels, etc. re now the hot, pardon the pun, topics. The way for Democrats to appeal to working men and women is through their pocketbooks first. Once you have improved their situation in this regard, they may not all of the sudden change into being social liberals when it comes to gun control, abortion or same sex marriage, but I'll bet you dimes to donuts they will be less likely to vote against Dems simply for those reasons. 
   Obama and every other significant Dem candidate need to hammer on economic themes right now and hard. If McCain is able to wedge his way in there, he has taken away Obama's trump card. I'm not sure Obama has watertight arguments or policies right now that will mitigate the hardship felt by blue collar folks everywhere but he needs to at the very least speak to it. Not with platitudes but concrete plans. A few well thought out policies beat many poor ones. Of course. This was the area where Hillary supposedly had the upper hnad but he can erase that if he hammers on the economy and where average folks stand. This is what the Democratic Party has been and ought to be about.

Reading Yoda's blog about the future of the GOP and the comments on it regarding what the Dems are (or are not) doing to keep theirs reminds me of an article by former Texas House Speaker, Liutenant Gov. and Democratic lion-Ben Barnes. The article is focused on Texas politics but could be extrapolated to include the national Democratic Party:
http://www.thetexasblue.com/we-need-focus-texas-problems-not-politics

The following quote, I think, distills the message nicely:
"Yet, regardless of whether a new Speaker is elected, if the House fails to focus on the serious issues confronting Texas, it runs the risk of becoming irrelevant. The power of being of being the majority party is often accepted as the simple answer, but it really isn’t. I’m all for electing a Democratic majority to the Texas House, but the above considerations must fit within our overall strategy of moving Texas forward. The strategy for winning back the Texas House cannot be predicated on winning a Democratic majority alone."

Obama's rejection of Clinton's and McCain's summer gas tax freeze is echoed by economists. Of course Hillary spins this into "he(Obama) doesn't care about the plight of the working class" boilerplate:
http://news.yahoo.com/s/nm/20080430/pl_nm/usa_politics_gastax_economists_dc