Feng Shui was first used to find suitable feng shui burial site. This system is called Yin House Feng Shui.
In Yin House Feng Shui, the location of the grave and surrounding environment can have a profound effect on the fortunes and well-being of the descendents. The ancient Chinese believe that souls are connected and families share karma. If the body (or bones) are correctly laid to rest and are able to tap beneficial qi, they can transmit these positive energies to their descendent and enhance their fortunes.
There are plenty of stories on how families have suffered because of an improper feng shui burial sites and others who have prospered for several generations because of good yin house feng shui.
Yin house Feng Shui is as complicated, maybe even more than Yang House feng shui. The natural landscape is very important. The proximity and orientation of nearby hills and mountains can greatly affect the energy in the area and hence the grave. The shape of the hills in particular can effect certain outcome. Unfortunately the intepretation can be very subjective since a dragon to one master may look like a snake to another! Needless to say a lot of experience is needed!
In addition to the surrounding, the orientation of the headstone, outgoing water and the selection of burial date is very important. Luckily the fomulas for these are quite well defined and not subject to too much variation in interpretation.
Yin House Feng Shui is still quite seriously practiced by some Chinese families. They are even known to dig up a grave and re-locate the body to a auspicious feng shui burial site if it is deemed necessary. And some of these works are done at odd hours like 3 in the morning!