As to why Obama lost New Hampshire, it seems clear the reason is that he was the victim of overheated expectations--as Hillary was in Iowa.

The latest polls were so over the top--in fact his team was trying to dampen expectations--to no avail. ( And there was no time to register the surge in women's votes due to Hillary finally "humanizing" herself.)

This also had the effect of causing overconfidence in his supporters. Some seem to have felt it was a foregone conclusion he would win. I've read that the "youth vote" percentage was actually no greater than in in 2004.   A much higher vote in general--but no "youthquake" --no huge surge of new young voters, out of proportion to the rest. Again, probably due to overconfidence.

Hopefully (take that, grammar police), his young supporters will learn from this.