Well, personally I chat about what they already know about keeping rabbits, the amount of research done before hand if a new owner speaks volumes. I have a look at the space where they are to be kept, ask if they are a home owner or rent, family commitments, holidays etc. Also I run through the most common ailments, teeth, eyes and the importance of vaccination giving a fair idea of costs and life expectancy.
It's also quite heavily based on the impressions given by people, those who are enthusiastic, willing to learn/already have. The animals welfare is what is important, firstly does this person want to give a good home, and secondly can they?
If you're on here, and are obviously wantng to do this correctly, I'm sure there will be no problem
Best of luck x