Once a photographic concept has been selected, think about what symbols might be used in an image. The best symbols to convey a message are often those that are widely understood, although less well known symbols can also work well in the sense that the viewer is obliged to work harder at interpretation.
Feel free to work with anything that seems to represent the concept of the image, or just a small part of it. Among the most widely understood symbols are those with religious, national and political connections. However, when using sensitive associations such as these always remember that other people may disagree passionately with your views. There is little to be gained by offending deeply held beliefs, so it is better to use an image to comment rather than abuse or ridicule.
Political concepts and messages are easy to find, not least because current issues are highlighted in newspapers and on television every day. Identify an issue about which you feel strongly, and consider how your own point of view might be conveyed visually. Choose a small number of available symbols with which to work, and try to put together a draft image using paper and pencil. Once a visual concept has been found, seek out the photographic elements and set about creating the actual image.
Other similar approaches may be conceived based upon national identities, films, humour, idioms, personal circumstances and relationships, environmental issues, sport, ethics, fiction etc etc. Have a look at some the currently published work on the internet and try to avoid copying and cliches.