I am one of those people that lives 12 miles from my nearest property, so I like to bundle appointments. I do it open-house-style twice a week, usually once in the evening during the week, and during the day on the weekend. I give a one hour window and schedule everyone that can come.
The benefit is that you'll always get at least one person to show. (Although I do sacrifice an hour, I use the time to read forum posts, and listen to podcasts on my iPad.)
A side benefit is usually once one person asks for an application, everyone at the showing will. In her book, Barbara Corcoran from Shark Tank said that as an investor, you might not want the deal, but once another shark makes an offer, you question what you missed, and you want the deal too. It's a herd mentality, I guess. So that's how I've applied it to landlording. If someone's on the fence, they get nudged toward wanting my house.
The point is, it's an efficiency for a small-time landlord, who doesn't have very many openings at one time. Like @Aaron Wyssmann said, my approach might not work if you have 200 properties.
I like the ideas from @Chris Martin. I think I will try that approach when I have another opening.