Review the company's website! You do not want to ask questions that are readily answered on the website. You need to show that you want to work for THAT company, you are not just after a job. I was asked once, "What can you tell me about my company?" No, I had not memorized the names of the top executives, but, I did know the area it serviced (electric company), other services it provided, their community outreach, and where it was I wanted to be in 5 years (school safety programs!)
A client once interviewed at a credit union. They asked her the difference between a credit union and a bank. She did not know. . .
So basically, do your homework about the company. And, as the other answer says, do your homework about yourself. Know what is on the resume/application you gave them. Have an elevator pitch, a short answer to "tell me about yourself" and answer for "We are interviewing 3 candidates, why should we hire you?" Your strengths and weaknesses, etc.
When you give your answers, do not recite them from memory. You need to speak candidly, the answers need to sound fresh.
Now, I usually recommend that people interview someplace they DON'T want to work, prior to interviewing with "the dream job." I call it "the practice interview." Don't feel bad about "using" them. Companies do it to us all the time. They already know who they want to hire, but, are required to do three interviews, so , you get the call. . .
Hope this helps!