No matter what project methodology you choose, it will require you first and foremost to define the scope of the project. The scope states what the objectives of the project are and what goals must be met to achieve success.
You can define project scope by identifying your goals, objectives, tasks, subphases, resources, budget, and scheduling. Defining the project scope outlines the parameters or limitations of the project and spells out what is excluded. That includes project by-products that are non-goals.
The scope must make clear to those involved exactly what product or service will be delivered. It is not intended to expand on methodologies or stakeholder purpose and motivation. How to Write a Scope Statement, by Bright Hub’s Eric Stallworth, is a step-by-step guide to this process. There is also a free, downloadable project scope template created by the same writer in Bright Hub's Media Gallery.
Ultimately, you will define project scope by identifying what initiated the request for a new product or service. It's useful to quantify objectives--"This service will increase the end user's efficiency by 15%." It's a good idea to characterize difficulties you've experienced without the product or service and what will happen if the project is not approved. You must describe what you are creating, how much money you will need, how much time it will take, and how many people you will need. The authorizing body will also want to know the limitations of your project as well as the risks involved.
You should set the approved scope statement aside as a point of focus as the project progresses through its stages. The scope will remind you of your focus if the project threatens to shift beyond its initial parameters. If there are any changes in the tasks originally identified for the project’s scope--no matter their size or who requests them--they are referred to as scope creep.
As the project manager, you can review the project scope and consider the scope creep. Your can then veto any changes to the original project plan, or you can initiate a change to the original scope. It is perfectly acceptable to anticipate changes even after you define project scope.