If the area you are building in has a steep slope, build terraces or steps made of logs or old railroad ties across the slope to divert water away from slopes and prevent soil erosion. Between the steps, spread a thick layer of wood chips to protect the soil. If the slope is gentle, seeding grass may be enough. Use splash guards on gutter outlets to help reduce erosion at the foundation of your home.
For home sites, the bottom line is pretty simple: You want soil that has good bearing capacity, exerts relatively low lateral pressure, and drains well, so that you can have a stable, dry foundation. The best natural soils for these purposes are sands and gravels. Silts and clays are fair, but the softest ones are poor. Then there are soils such as peat, expansive clay, and improperly deposited fill, which are so bad that they must usually be removed and replaced – often at considerable cost to you.