Conversely - I see Obama's path to reelection-
#1 - Confuse the crap out of the independents and blue-dogs and get more of them to tune out and stay home than switch to Mitt. This is why negative campaigning from Obama will be off the charts. I don't know the numbers but say it went 70/30 in his favor last time around and represents about 20% of voters. If he loses 25% to swing to 45/55 I think he loses decisively. If he shrinks the turnout to represent 10 - 15% of voters, it needs to swing a lot further and becomes harder to lose.
Distant second - If he can keep his base and erode Mitt's he can make up for the lost votes (again, I have not seen a single person say they switching from McCain to Obama or stayed home last time to definitely voting Obama this time). Conservatives do not have their lead guy in Mitt, Obama my be able to benefit from kooky fringe baptists staying home b/c they think Mormons are weird and untrustworthy, almost as bad as Catholics like Ryan. If the religious right stays home, it hurts Mitt substantially. To them, his waffling on abortion issues is toxic and may be the demographic more single issue than any. Getting them to stay home may be tough as I don't think they ever stay home.
Military spending and Iran may be an issue Obama can win votes in the middle. Convince people that anyone serious about spending has to have the military on the table. Weak on Iran may play OK since we are a war fatigued nation. Let them sabre rattle and point out we get our oil from Canada and South America. China has an Iran problem not us.
Acknowledge defeat on the economic issues by deflecting and avoiding that fight. Obama can't win this one. His positions only resonate with his base and they are frankly wrong on improving the economy. Average people want work and pay raises. Environmental issues are a luxury we cannot afford.
Youth vote - I dunno. Unemployed living with Mom and Dad kind of sucks. Working Starbucks with your college degree, kind of sucks. All those old people keeping you from even getting a job at Starbucks, kind of sucks. 6.8% student loan interest rate (versus 2.5% pre 2008), kind of sucks. 6.8% interest in a 0% interest world feels like someone gave you a roofie and a rough ride. Obama is attacking this issue wrong talking about Pell Grants and not getting lower interest rates. Then again, he might have to admit Bush did SOMETHING "right".