Just a quickie, I ran into this post by Seth Godin and had to mention it here.
If you click the link you will see that an apparent idiotic idea of giving away gift certificates completely unasked and unadvertised at a store is a boon to sales as it inspires the buyers to start shopping again.
How can you use this. Well every time that you send a buyer listings ask them again what they are looking for. Not only is the feedback good for you but the buyer will become re inspired to start looking again. This would be best to use with buyers that are not yet motivated but will hopefully be soon.
Another thing to do is to send the buyer a checklist of things to look for in a new house. Do they want an attached or detached garage? What kind of kitchen? How big a back yard? Will they need a toolshed? They have to visualize these things to tell you.