Your project will have a set of objectives to achieve or reasons why it was set up. List your objectives and for each one write down the tasks that need to be completed to achieve the objective.
If there is anything you are unsure about, do your best to find the answers you need to clear these up.
Decide on the project team and secure any sign off (from line managers or clients) needed to set up the team and project.
Writing Your Plan
Now it's time to write your plan. You may decide to write the plan by yourself and then talk it through with your project team. The other option is to write it with your project team, although this may feel slower it may encourage the team to own the plan and the project. If you have an experienced project team, the plan will benefit from the team's skills and experience.