Project planning is the art of breaking down the entire project into distinct logical units of work that are tangible in terms of labor and cost and being able to assign resources based on capacity and capability in order to be able to execute these logical units of work with a feasible estimate. At this stage in the project, when the Requirements have been defined, Cost Benefit Analysis and Scoping has been completed, Project Planning can begin.

Though a perfect estimate is almost, always impossible to predict, estimation is the art that defines effective Project Management. The ability to evaluate individual resources, their capability, and the task at hand combined with the materials needed by those resources in order to achieve the tasks, often evolves over time. Planning alone will lay the entire project out for the team, making it easier to visualize the execution and see where failures could happen and contingency plans can be laid.

Usually, this activity is done in multiple stages using a tool like Microsoft Project, or the open source alternative - Open WorkBench (openworkbench.org).

1. Break the project down into a hierarchical organization of tasks, subtasks, sub-subtasks and so on to achieve a linear representation of each logical unit of work
2. Lay the dependency between each logical unit of work in order to arrive at a sequence. Some tasks may happen independent of the other, enabling you to parallelize the execution, while some cannot begin until some others end, indicating dependency.
3. Identify resources on a project-wide basis along with resource-availability information - schedule, work hours, etc.
4. Tie each resource to a task based on the effort required to complete that logical unit of work and the resource's availability and even capability.
5. Arrive at a logical end date for the project to complete execution.
6. Dependency is important - if one logical unit of work takes more time, or does not occur, the tasks and subtasks that depend on that task will take that much longer to complete, or may not complete.
7. Parallelism is important. It is crucial to not have resources waiting to complete their individual tasks because it has a dependency on another task. Therefore, it is important to break down the project's execution into as many parallel streams of execution as possible so that resources can get work done independent of each other.
8. Visibility - if the Project Planning is done effectively, and a good plan is in place, any abnormal activity or delay will affect the final deliverable date, thus providing management an optimized view of the deliverables. This is key.