Congrats on the interview. First take a deep breath and relax! I show the parents the home and while showing each area explain what we use it for activities that take place and the routine. After going through the house we sit and go over any questions they might have. ( I do a phone interview before my home visit so the parents already have a good run down of my policies and procedures. ) So after the tour I give them a hard copy to read over. I usually have toys out for the child and silt and play with them while parents read through. I answer any questions they might have. Usually about schedule, pay, routine, closure days, etc. my interviews take from 30 minutes to an hour. I always have a copy of my policies and procedures for them and a list of the dates I'm closed. I take notes while we are taking about their child's routine, Development, etc.
If the interview is iffy ask if they have questions then say I will be in touch soon. Later that evening email and say they weren't a good fit for your daycare.

I always double check to make sure I know start date, f/t or p/t status, hours required, allergies/restrictions, rough schedule of child, birthday, likes dislikes, etc.

I had a family sign right then. I knew it was a good fit so I got all the paper work and they filled it out while I interacted with the child.

Good luck. Hope I helped!