Depending on just how broad you can be, and what resources you have available... (and apologies for of course steering you towards what I am most familiar with).

You could take a look at postcards as a form of colonial propaganda. In order to be unique you could focus on a particular time and space and think about what the postcards were supposed to convey and what they might indicate about the power relationship between the place the postcards are about and where the visitors would be sending postcards back to. The Pacific provides a great place to start thinking about this; postcards have a long legacy there and the exotic/wild/paradise/erotic/edge of civilization motifs provide a plethora of examples of how postcards were meant to sell the idea of 'paradise,' convey a sense of longing, lack of civilization, how postcards could be a part of the discourse that justifies colonial holdings far removed from the metropole (think Tahiti/France, Britain/Fiji, even Hawaii/US), and how the postcards fit in with Orientalist discourses of power over sign and symbol. Or just focus maybe on one of those aspects depending on how long your paper should be.

If you were interested in going that route here is some good starting literature:

• Miriam Kahn, [Tahiti Beyond the Postcard] (http://books.google.com/books?id=Z6yqXzx0ToEC&dq=tahiti+beyond+the+postcard&source=gbs_navlinks_s)

• Edward Said, [Orientalism] (http://books.google.com/books?id=66sIHa2VTmoC&dq=Orientalism&source=gbs_navlinks_s)

• Patty O'Brien, [Pacific Muse] (http://books.google.com/books?id=n2Sv0gysRhUC&dq=O’Brien,+Patty.+The+Pacific+Muse:+Exotic+Femininity+and+the+Colonial+Pacific.+Seattle:+University+of+Washington+Press,+2006.&source=gbs_navlinks_s)

• Bernard Smith, [Imaging the Pacific: In the wake of the Cook voyages] (http://books.google.com/books?id=aePdPAu_PTIC&dq=Bernard+Smith&source=gbs_navlinks_s)

• ",", [European Vision in the South Pacific] (http://books.google.com/books?id=tk6cdwQRAWUC&dq=Bernard%20Smith&source=gbs_similarbooks)