Most high-end buyers are very internet savvy, so I would make sure the listing is all over the internet. An easy, one step way to do this is to put your listing on Point 2 NLS (http://nls.point2.com/). They will syndicate it across the web for free. Be sure to click the option to join without a website if you don't want to set one up. Of course, if you don't have a website, they will give you one free for six months.

You should also determine who your target market is and tailor your advertising to reach this market. For what type of person would this house be best suited and what can the person do in the house? You can determine this by the best features the house offers.