One thing you might want to try is giving your users a reason to fill out the form. For an example, see this site I worked on: http://www.bigislandreale.com/232548-Puakea-Bay-Ranch-Puakea-Bay
Another thing you can try is to make it clear who the form is being sent to. If possible, put a picture of the recipient by the form. It may make people feel more confident that their email will be sent to a real person. Trulia does a good job of that - http://www.trulia.com/property/1065233184-40820-Kuhio-Hwy-G306-Kapaa-HI-96746.