Sarah Wildman has a useful retrospective on the Sarkozy-Royal campaign, detailing some of Royal's gaffes and missed opportunities. It's probably a bad thing, for instance, to telegraph ignorance over whether the Taliban still rules Afghanistan. And it seems that Royal tried to handle Sarkozy's hardline on immigration much the way Democrats approached Bush's war-mongering in 2002: Ignore it, hope no one mentions it, move on.
As for Sarkozy's winning strategy, Judah Grunstein has some interesting reflections on his campaign. Sarkozy made an early play for the xenophobic supporters of le Pen and, to some degree, got them. This sort of fouls the American media's representation of him as a brave liberalizer, though. "[T]he dirty little secret of his victory," write Grunstein, "one that the American press seems to want to ignore at all costs, is that he owes it in large part to an anachronistic element that believes, among other things, that France should withdraw from the EU, close its borders to immigration, refuse citizenship to anyone without French "blood", and give preference in jobs and entitlements to French citizens. Hardly the kind of reforms the American press had in mind." Now, whether Sarkozy may of course do as the Republicans have often done in this country and ignore the more savage elements of his base. Or he may not.