Coming from someone that has spent the last year looking for "the perfect job" and going on hundreds of interviews....my only advise is to ditch the "canned questions" I know how to answer each one exactly the way you want me to but that doesn't mean I am right for the job, it means I know how to interview.
Interviewers spend way too much time asking irrelevant questions.
Tell them a little about the company, don't look at their resume for the first time in the interview (know who is coming in), do not tell them what you are looking for yet, I would change my answers to give the "correct" response. ask them what they are looking for, ask them about their relationship with their previous bosses / employees (that will tell you alot about the person) trash talking is obviously bad but to hear that there was conflict is not bad, this is real life, not everyone gets along with their ex-boss., make them comfortable so they can relax and be honest with you (most important), don't ask why they want this job...come on, they need a job, don't make them feel like a loser.
Tell them when you will make a decision, kepp them there for an hour instead of making them come back if possible. Judge their character as best as possible. Don't ask if they have any questions for you..that puts them on the spot to go over everything you have told them and think of a question in an instant and if they can't, it's uncomfortable. Just talk, listen (mostly) and have a normal conversation, get to know them, follow up with them when you say you will (you might want them for another position next week) and be respectful.