Debbie Kettler was interviewing a college senior for a job at Mercantile Bank. The student had spent the summer working at another bank, so Kettler asked about the experience.

"How big is that bank?" asked Kettler."Oh, about three floors," said the student.

End of interview.

Banks are measured by their asset size - generally many millions of dollars - not the size of their building. The story shows the biggest mistake new graduates make when heading into job interviews.

"Students don't prepare. These days it's prepare, prepare, prepare," said Kettler.

Kettler, a former corporate recruiter, now sits on the other side of the table as director of placement at the University of Missouri-St. Louis. Her job is to help students find jobs.

To impress a recruiter, a student should start in the library. Study the company and its industry, she said. "If you're interviewing with Pepsi, know that they own Frito Lay," she said.

In a Northwestern University survey, corporate recruiters said their "single biggest turnoff" was an applicant's ignorance of their company. Come prepared with at least five questions for the recruiter designed to show you know the company and have thought about its future, Kettler advises.

Preparation is getting even more important these days. Today's graduates are competing against legions of laid-off workers for entry-level jobs. Recruiters routinely get 300 to 500 resumes for each low-level opening. With that much paper to wade through, a single typo will destine a resume for the circular file, he said.

As a recruiter, Kettler often favored open-ended questions with no right or wrong answer. They were designed to plumb the quality of a student's mind, the ability to communicate, ability to prepare and to think rationally about the future.

Expect questions such as: "Why did you get a 2.8 grade average? Why not a 3.5?" "Why should I hire you?" "Name three of your weaknesses. "

Kathy Bersett, a Washington University senior, remembers a question that stopped her cold on her first job interview. She'd mentioned that she'd worked part-time in a Subway sandwich shop. "Compare the profitability of Subway to that of McDonald's," the recruiter commanded.

Now, with one job offer in the bag and more than 20 interviews behind her, Bersett could handle a question like that without blinking. "The more you interview, the better you get," she said.