Project goals: Why, not How
The most important factor when starting a project is to define the goals of the project clearly. A goal doesn't have to be complex, it is often better to try to keep the description of a goal in a few lines of text, pictures or drawings. Project goals should clearly state why the project is being done, but ideally should not address the issue of how the goals should be reached. If the exact implementation method is fixed in the goal of the project, it can make the actual implementation process immensely more difficult and thus more expensive. Since Drupal, or any other system based on ready-made functionality, offers a huge variety of different possible implementation methods, it is much more sensible to approach the project from the point of view of the goals and leave the studying of more detailed ways of implementation (how) for later.

Project goals should be clear enough for entire project team to fully understand and simple enough to be used in project communication to external parties. Based on the project goals we should also be able to set criteria that will be used to measure if project is successful or not.