The best photographic work tends to come from photographers who are passionate about their subject. They care deeply about what they portray, and consequently see deeper in to a situation than others. The passion of a photographer is ultimately revealed in the images he or she produces. Indeed some excellent photographers can be identified by their subjects and the way in which they portray them.
With personal interest and commitment in mind, it should not be too difficult to select at least the broad subject area in which to work on an essay. However, choosing exactly where to focus can be more challenging. Most stories gather depth and breath as they are more closely examined, and there are inevitably countless ways in which each story can be told. It is also often the case that stories may be found within larger stories, so depth and focus may need to be carefully considered prior to staring work and some limitations of scope may have to be applied. For example, a subject such as poverty might be addressed on a global scale. However, it might be more practicable to tell the story of poverty in a particular country, city or locality. If a particular city is chosen, a decision must then be made regarding which areas or streets to portray.
Where a choice of subject proves difficult, try the technique of brainstorming. Start by writing down a list of issues about which you feel strongly, and evaluate each one with regard to practicality and what openings or contacts might be available. Caring about poverty in Africa is one thing, but the expense of portraying it successfully when based in Europe is quite another! Also consider what opportunities and resources exist locally, perhaps guided by stories running in local media. Then, having eliminated most of the ideas, do some basic research regarding the remaining subjects on the list, and see where it leads. Always remain flexible with regard to subject choice, and follow research and the evolving understanding of a story wherever the evidence takes it.
Local charities and volunteer organizations are sometimes interested in photographic projects related to their particular cause or work, and it is possible to get involved initially by offering support in a relevant field. Resources also exist on the internet. Collective Lens is a non-profit organization which strives to create awareness of people in need around the world through photography and by using the social media.