If your house is not priced competitively, people looking in your price range will reject your house in favor of other, larger homes for the same price. Overpricing usually increases time on the market, and that adds to the carrying costs. Ultimately, many overpriced properties sell below market value. Owners who fail to make necessary repairs, who don't spruce up the house inside and out, touch up the paint and landscape, and keep it clean and neat chase buyers away as rapidly as Realtors can bring them. If you were selling a car, you would wash it, or maybe even detail it to get the highest price.
Houses are no different.
It's difficult for them to do that if you follow them around pointing out every improvement that you made. It may even have the opposite effect you want, by making them feel they are intruding on your private space. Resist the temptation to talk the entire time a buyer is there, and let them discover things on their own. Try a tasteful sign to point out some hidden amenity that they might miss. No question about it, Realtors will only bring qualified buyers, and these will be fewer than if you open your front door to everyone who walks down the street.