The Obama campaign has problems with conservative populism. They don't seem to understand it.
McCain won because he used short answers, and answers that reflected deep conservative values. Obama hesitated, tried to give nuanced answers, and came off looking like he had no values. Obama needs to train, to give fast, straight-on, inspiring responses that link his major themes - empathy, responsibility (both social and personal) and aspiration - to the foundational ideals of our country. Obama's values are America's values, and that has to come out loud and clear.
Additionally, he must show just how extremist the McCain/Palin ticket is.