Before the interview, I read over the candidates resume and jot down an interview plan on a scrap of paper. That’s just a list of questions that I want to ask. Here’s a typical plan for interviewing a programmer:

Introduction
Question about recent project candidate worked on
Easy Programming Question
Pointer/Recursion Question
Are you satisfied?
Do you have any questions?

I am very, very careful to avoid anything that might give me some preconceived notions about the candidate. If you think that someone is smart before they even walk into the room, just because they have a Ph.D. from MIT, then nothing they can say in one hour is going to overcome that initial prejudice. If you think they are a bozo because they went to community college, nothing they can say will overcome that initial impression. An interview is like a very, very delicate scale—it’s very hard to judge someone based on a one hour interview and it may seem like a very close call. But if you know a little bit about the candidate beforehand, it’s like a big weight on one side of the scale, and the interview is useless. Once, right before an interview, a recruiter came into my office. “You’re going to love this guy,” she said. Boy did this make me mad. What I should have said was, “Well, if you’re so sure I’m going to love him, why don’t you just hire him instead of wasting my time going through this interview.” But I was young and naïve, so I interviewed him. When he said not-so-smart things, I thought to myself, “gee, must be the exception that proves the rule.” I looked at everything he said through rose-colored glasses. I wound up saying Hire even though he was a crappy candidate. You know what? Everybody else who interviewed him said No Hire. So: don’t listen to recruiters; don’t ask around about the person before you interview them; and never, ever talk to the other interviewers about the candidate until you’ve both made your decisions independently. That’s the scientific method.

I hate this moment in interviews when a potential employer asks how much I want. the range of what I could ask for in my industry is wide and the trade-rag statistics don't really help me either. so I usually go with what I think is fair. sometimes that's right-on but sometimes it's too much and sometimes it's too low.