Some job interview advice from Karen Kelsky: "The 'Be Yourself' Myth".
[Y]ou have to create a professional persona. That persona is a full-fledged adult who demonstrates a tightly organized research program, a calm confidence in a research contribution to a field or discipline, a clear and specific trajectory of publications, innovative but concise, non-emotional ideas about teaching at all levels of the curriculum, a non-defensive openness to the exchange of ideas, and most importantly, a steely-eyed grasp of the real (as opposed to fantasy) needs of actual hiring departments, which revolve ultimately, in the current market, around money.
I have many friends on the job market this year. The advice isn't precisely pertinent for postdocs, but with some small alterations it still works.