This is what I do....

-a parent will email me via my ad on an online site
-I email the parent's my parent package (contract, permission forms, sick policy)
-if after reading my contract they are still interested, we set up a meeting. I do this because I don't want to waste my time meeting with ppl who don't like or aren't going to follow my contract
-I ask them to bring a list of questions to the meeting and I can answer in person and they can view my home and daycare.
-meetings typically last 30-60 minutes and I set them up for during work hours. This way I can see how their child interacts with my current children, they can see how I interact with children and I'm not giving up my free time. My groups have always been well behaved and they like visitors so it's not an issue for me. I know some don't like it because it can be chaotic though
-I ask the parents to let me know within 3 or so days if they want the spot
-I have a list of parents on my waiting list but I don't set up meetings until a spot opens up.