You're looking for "experienced" people-
We have no problem finding folks who will "get along", so we dispense with the touchy-feely stuff until after we know they've got the technical chops. Sure, you're also testing for the basics, like ability to communicate etc. while you're asking the technical questions.
We find lots of folks who lie on their resumes and never expect us to validate the depth and breadth of the experience they say they have. It's those that we're trying to weed out- the quicker the better. Don't get me wrong- padding the resume is a time-honoured tradition- but if they say they've "worked with P&IDs", I want to know if that meant that they've developed P&IDs from scratch on a daily basis, or that they've seen a P&ID- once, on someone else's desk!
I'd ask a few technical questions that can be answered over the phone. The good candidates will not only answer them, they'll perk up when you get past the touchy-feely personnel bullsh*t and get into testing their knowledge of what they do for a living. The really good candidates won't guess at what they don't know- they'll reason from what they DO know and tell you exactly where they'd look to find the asnwers to the questions they can't answer off the top of their heads.
I'll also ask them what sort of work environment they're used to: a compartmentalized one, where they specialize in their job description and have lots of subject-matter experts to depend on for answers to the tougher questions, or one where they've been acting as a jack of all trades (master of none). That's a basic fit question for a workplace.
Which questions should you ask? Depends what sort of work your firm does! You know better than I would. If you're looking for 5-10 years experience, that's what you're testing for- is the experience they claim available, and relevant? If the experience is NOT relevant, do they have access to the underlying fundamentals necessary for you to have a hope of teaching them what they need to know, or is it buried under 5-10 years of dust and rust and disuse?
Totally different strategy for fresh grads, or other job descriptions.