The title seems to indicate that you are trying to do shaded relief on buildings when what you are looking for is the terrain underneath the buildings. First, try Pyrandon's tutorial for towns or cities, can't remember the proper terminology he used. It covers the terrain as well as the buildings. Second, I did a faux National Geographic shaded relief tutorial. Third, there is a specific link to an off-site tutorial for shaded-relief which might be in the tutorial section or in the reference material section...the link is something like shaded-relief.com. Fourth, just dig around in the tutorial section to see what catches your eye. Fifth, try using the on-site search box for "shaded relief". Lastly, you might try to provide an example of the type of map which you are looking to replicate and not one which you are just starting. Hope this helps somewhat.