Having been very involved with my department as an undergraduate (at a relatively large public liberal arts college), I have some idea of what happens in the hiring process. My professors may have afforded me a rare opportunity, as I am not sure many students have the experience of interviewing Ph.D.'s seeking to be hired as a professor. I will try to share some of the key lessons I learned, although I will have to be somewhat generic as a matter of courtesy, and out of respect for the privacy of the individuals involved.
(a) While sometimes faculty are sought because funding exists for a particular field, one might actually be well advised to choose a field for idealistic reasons. It should come across that you truly care about your research. Not only should you be able to answer for why your research is of social significance, but also for why it is significant on a personal level. Passion counts.
( Be careful not to get bogged down in your own research. Your advisors may do you a disservice if you or they are preaching to the choir. Anticipate questions from faculty not particularly interested in your area. You may not always agree with contrarian advice, but advice from those with an ideology antithetical to your own can help as not only will you improve your paper, clarifying and improving your arguments, but you will be ready when questions inevitably come up during your presentation in front of a hiring committee.
© Do something interesting. Take risks. Even the most highly awarded individuals, by playing it safe, can do surprisingly bad when presenting their research. A novel idea can be more attractive than a well-written, well-researched dissertation. Just be sure that you know your stuff, methodologically.
(d) Do not coast. A paper of convenience might be okay, but a dissertation...