When you are invited to an interview the institution should indicate what sorts of things they will be expecting from you. Many will give you a schedule of your events. It is perfectly acceptable to ask about the conditions for a job talk (or classroom presentation): How many people will be there, what kind of tech will be available, who the audience will be. Be sure to ask about time and whether there will be Q and A after. These questions show that you really want the job because you are willing to tailor your performances to their conditions.
You have to know the audience and the kind of institution interviewing you to ace your job talk. Is the audience going to be department faculty, a mixed audience including students, and if there are students are they undergraduate or graduate. People are going to be assessing the talk both as an indication of the quality of your research AND your ability to interact and communicate in a classroom. Those are not always the same things, but the ability to make people care about your topic and go away interested intalking with you more about it would be the best outcome.
Mentoring Discussion Series, Question 7:
What are the keys to giving a successful job talk?