Architectural photography is a very broad genre that ranges from real estate snapshots to dynamic abstract art. Despite the many variations, one thing most architecture images do attempt to do is highlight the grandeur of subject. Sometimes the historical/cultural significance is what draws you in and sometimes it's simply the uniqueness and intricate details of a structure (particularly modern architecture).
1) Photograph architecture in either an urban or rural setting.
2) Try different ways of composing the (i.e. more or less of the surroundings) to see which has the most impact.