Do not take your on-campus interview lightly. Although it was "free" to you and easier to come by than direct contact with the company, the competition is intense.
To ace your on-campus interview, you will need to read (and study) all of the information contained in the Interviewing Success section of this book. All of the preparation. All of the questions. All of the techniques. All of the strategies. Be prepared in advance.
If you treat every interview as if it were your last (in both a positive and a negative sense), you will be more focused on affecting the end result.
On-campus interviewing is a gift. Treat it with high value.