1.) When I hired co-op students in a previous position, I had a lot of luck with an interview style that a cognitive psychologist friend of mine suggested. I would switch between memory questions and creative questions. For example, I would ask:
"Can you tell me about a specific time when you have had a conflict with a co-worker?"
then
"Imagine that I am Steve Jobs and you are pitching me on some new features that would make an iPod more useful. What features would you recommend?"
I found a couple of things with that style. First, it was an easier way to figure out who they are and what they were like to work with. Second, it showed me a lot about how they could think on their feet and come up with creative solutions on the fly.
Also, honestly, don't overthink it. You're trying to hire someone who you are going to want to spend a lot of time with. Don't expect perfection off the bat, and if I were you, I wouldn't optimize for skill or experience. Instead, optimize for someone you want to spend 40 hours a week with for the next twenty years. Your relationship with this person and your ability to teach each other things will be key to the relationship.
Also, when you hire them, I strongly encourage you to build a culture where you encourage them to teach you how to become a better manager. This starts during the interview - be upfront that this is a first for you and you want to learn how to become the best boss they've ever had. Ask them to give you frank feedback whenever it comes up. Ask them to do performance reviews on you. And schedule frequent one on ones where you encourage them to teach you how to become the best boss they have ever had.
That kind of culture is amazing because the more comfortable and skilled they get giving you feedback, the more comfortable and skilled they will get receiving feedback from you.
Good luck!!
2.) I'd avoid books. In fact, if I were you, I'd be very careful about taking any of the advice I gave you in #1. Those are just things that worked for me, and books are generally composed of things that work for the authors. You need to figure out your own style and what works best for you and your organization. Once you figure that out, hiring will get easier because you'll have an idea what you're selecting for.
I can't believe I just wrote a wall of text, then told you to disregard what I said. :)