People do visit a lot of houses when they are shopping. The homes start to run together in their minds. It is a truism in the industry that people will buy the most recent house they remember after they start to tire of the shopping process.
Change that dynamic by coming to the tour with a high-quality digital camera. Take several general photos, but then ask your prospects which particular features they would like photographed. Explain that you will mail them the prints. This not only gives you great insight into the things they find attractive, it also helps memorialize that warm fuzzy feeling they had when they saw those features.
They start seeing themselves in the house, enjoying those features. You gain a significant advantage over other properties on the market.