Interesting question. You will want to follow a lot of the same principals that you would when building any lot that you plan building on. What are the local building codes? Are utilities accessible to the the lot? Are there any environmental impacts that need to be considered when building? How is accessibility to the lot and building site? One of the main issue that you will want to make sure of is soil stability. There may be some significant engineering involved depending on the pitch of the lot and soil stability.
When considering building you will want to work with someone who understand the local ordinances/building codes and who also is familiar with some of the challenges of building on slopes.
Hope that helps!
Alain Pinel Realtors