I love to list homes where there are pets, especially cats since I have a little DSH ginger tabby named Zoey (Figure 1). However, sometimes there are cat odors that need to be dealt with in order to make the home fresh, and one can't always move all the furniture and have a good flooring professional come in and really clean everything.
Figure 1
What I do is make the house fresh while I'm there by putting a group of 3-5 candles in strategic locations. I don't even have to light the candes in order for the wonderful smell to start freshening up the place. I like to use a tall candle, two medium height candles, and two smaller candles. They can be used over and over and over again. Always use a base of some type for the candle since a bare candle on many surfaces can stain them. I like to use old CDs (I must have a million AOL CDs!); just turn them upside down and one has a nice, shiny surface.
Another secret is potpourri, but if one isn't careful, some potpourri will overpower the house which can be just as bad as the pet scents.
One more thing I do to freshen up the place is make sure that there is some greenery in the house. I have lots of small plants in tumble-proof and leak-proof pots that I can set just about anywhere. One can also use fake plants, though (see Figure 2) I prefer vines, such as English ivy (Figure 2), heartleaf ivy (Figure 3), and pothos ivy (Figure 3) since they can create a mystical environment when their vines are hanging over the side of the refrigerator, or off the countertop in the bathroom, on down the sides of the tall bookcase (see Figure 4).
Figure 2. Fake English ivy.

Figure 3. Pothos ivy (top and left) and heartleaf ivy (right and bottom)
Figure 4. Heartleaf ivy on tall bookcase.
There are also some succulents that can add dimension to a vacant tall corner, such as the draceana and the aeonium. If you don't have a green thumb (I don't, but my partner does), stop by your local grocery store or home improvement store and get some throwaway kalanchoes or cyclamens. I say "throwaway" because it is almost impossible to keep them and get them to bloom the next season; the geneticist have interfered with mother nature.
All of the above plants can be watered on Monday, after the open house, and they'll be dry but alive next weekend for those open houses.
And lastly, if there aren't any books in that tall bookcase, I don't mind loaning a few of mine. I prefer books about classical composers, travel books, classic books (The Catcher in the Rye, etc.), and general interest books like the Guinness Book of World Records.
I then love to listen to prospective buyers ("Oh, look at that ivy!" or "Hey, look at all the travel books.") and then gently break in about the ivy or the travel book, or the candles, or the potpourri. There are many ways to break the ice and get a conversation going to establish some rapport with them.
One thing that working for Borders Books and Music for 30 years before becoming a Realtor taught me was that music, scents, books, and plants can have a very calming and influential effect on people. Just make sure when you're trying to sell a home that it's the right type of music (no explicit lyrics--sorry rap and hip-hop), scents (cat and dog odors), books (no porn, not even soft porn), and plants (no thorny cactus, and if you use roses, remove the thorns)!
Cute cat, right at home I can see. She looks like SHE is in charge!