A problem tree is a common tool for project planning. The idea is to identify a focal problem for the project and then look for the causes and effects of this problem. This should help you to identify the target group that you want to work with, important issues in their context, as well as the kinds of stakeholders you need to take into account in your project.
You can use the template below to draw your problem tree. This is a very simple version of the problem tree analysis. More sophisticated versions exist elsewhere (e.g. in the sourcebook of sound planning of ESF programmes).