Frankly, interviewing is a pain from the hiring manager's perspective. It take's time out of the day, and time away from other commitments. (S)he would like nothing better than to say "This is the one!" and not have to do another interview to fill the position. Everyone is looking for that candidate who can be a trusted team member that makes work less stressful because (s)he is always willing to step up, contribute and be accountable.
Keep this in mind:
The more junior the interviewer, the more formal the slate of questions you will be asked. Let the interviewer take the lead, and follow along wherever (s)he would like to go.
The more senior the interviewer, the more likely it is that (s)he will be handed your resume on the way in the door.
In the latter case, take advantage of the situation to show off what you’ve learned about the organization and present your strongest accomplishments. The more you tee up the conversation for the interviewer, the better things are likely to go.