1) The Tea Party ruined any chance of the GOP nominating a candidate who would have been an acceptable alternative to a large enough number of independents to swing them, and the election, from Obama to the republican candidate.
2) Once nominated Romney waited too long to pivot to the center...thus when the 47% remarks hit the news, he was toast.
3) The brutal primary left Romney with little cash on hand, while Obama was flush. The Obama team had a field day defining Romney in the most unfavorable light possible. Ann Romney gave us a bit of insight into why this happened when she told some television host or another (I don't remember which) that "Mitt is really cheap" He spent $40 million of his own fortune seeking the nomination in 2008, obviously he decided not to do that again. It was a fatally bad decision.
4) Voter turnout was lower in 2012 than in 2008, but it seems this time the lower turnout favored the Dems as some real right wingers stayed home.
5) Obama had a built in constituency of African Americans....the GOP overestimated how many were disenchanted with his first term.
6) Obama was very wise in the timing of both the executive order to stop deportations of young Latinos/Latinas and his support of gay marriage. Neither were done so far in advance of the election so as to be easily forgotten. Women needed no further prodding once the GOP revealed its basic misogyny.
7) The Obama campaign team is brilliant. Hope they go to work for the Democratic candidate in 2016. That candidate will not have as many people willing to stand in line for up to 9 hours in order to vote. I'd be willing to bet that thousands of would be Romney voters took one look at the lines and decided to go home....particularly as the fools on FOX were guaranteeing a huge Romney victory. 
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