I like to ask other managers what kind of questions they ask during their one on ones. Everyone has their own style, so I often get some interesting responses. Getting good information out of your one on one conversations is something of an art. Given the amount of time over a career that you will spend during one on ones, it's worth a small time investment to improve your skills.
Schedule one-on-ones with direct reports, keep them on the same day and time, and never cancel them. - Lopp, Michael (Managing Humans)
This book is commonly held up as the work of God when it comes to managing people. Here are my blatant crib notes of the text.
When you're stuck, Michael suggests some emergency topics.
This is a variation on "How are you"? This does lead to a status update most times, so you often need to redirect. It's important to lead with something that lets people talk about whatever they want.
More direct question to get at their mood/happiness.
Give the employee permission to say that they don't like their current project, as well as implicitly tell them that it's something we can change.
Is there some asshole that's bothering you? Maybe I can help.
For some people, work friend ships are critical.
We should try to hire them.
Are you thinking about the long-term future of the software? I care about what you think!
I try to ask this as often as I can, but often forget.
i.e. - how much insight into the sausage making can you stomach? Is that motivational for you, or counter-productive?
One thing I like to do is change the scenery of a one on one. Taking a walk outside is a great idea. I also like to do a one on one over lunch occasionally. On the other hand, you definitely want to be in a traditional conference room if you need to give hard feedback, or have a tough conversation.