There's a lot references how to do a I.T. interviews, so of course will spend you of more about this topic except by one little thing, a little question that is, for me, a good one to fell how comfortable is the candidate with the technology of the job.
Say Java, ask something like: "What feature of Java annoy you?" or "What feature of Java that you don't like much and could be improved?".
The point here is very simple, is easy to say the advantages but requires a lot more know how to no the problems. The answer don't have to be perfect, sometimes we think that one thing is annoying without knowing that is the best. To change opinions is part of growth it's natural, but have a opinion is more important.
Answer this question is harder for someone that never thought how improve their processes, or took a technology as a final solution, or another things that annoys me as well.