I have a friend who happens to be an SEO expert. He has shown me a number of properties he has built and sold for both 6 figures and 7 figures. The basics are always the same. First he finds a highly searchable category that its users would either buy that categories product or generate sellable leads from individuals going to that site. Next he tries to buy the .com and only the dot com. The domain can be 1, 2 or 3 words as long as its .com. I have seen him buy names as low as the low 5 figure range. Next he builds a site that is search engine friendly. The site has to have lots of fresh content. A link building campaign is the last part.
It sounds as easy as making a cake but of course its tougher than that as many domainers are looking for the holy grail. But if you have or can hire someone with the right skills and follow that approach, you will be going in the right path to success.