When designing the exterior appearance of a building, it's important to consider how the building will relate to its neighbors. One aspect to consider is whether the building should express unity with its neighbors, or debate an alternative with its neighbors.
Consider scale, form, materials and other aspects of neighboring buildings. Use similar scale, forms and materials to make a building that declares unity with its neighbors and helps to form a feeling of community.
At the same time, choosing some different forms or materials can express the indvidualism of the occupants and debate other possibilities with neighbors.
For example, in this image of new houses in Amsterdam, each home is of the same height and width, with similarly located entry doors. Yet, each home has a unique and sometimes whimsical facade that differs from its neighbors in shape, details and materials.