When project schedules are created, the project team needs to make sure that all the tasks, phases and milestones are accounted for so the project can be finished. The project manager needs to make sure the key steps for success are included in the original schedule and all of the estimations go into the schedule. Following these steps will ensure that you are planning for success when you create the project schedule.
The first thing that you need to make sure is correct is the scope estimation in the project schedule. The initial scope statement and the charter should be complete and approved by all parties and now it is time to turn that into a schedule of all the tasks needed to accomplish that scope. This is not the time to open up a schedule from an old project and make a few changes and call it the new schedule. While old project schedules and templates can be helpful, the scope for the current project must be estimated correctly and plotted out in the new schedule in order to ensure that all of the scope is accounted for. There is no short-cut to this work; that will only create more problems down the road when you realise that the template or the old schedule did not account for everything in the scope statement and part of the project has not been estimated and included in the schedule.
Once the scope has been estimated, then it is time for time. The time estimates should be based on actual experience whenever possible. Using guesses or just plugging in the times that get you to the finish date the stakeholders or customers request will only create more problems for everyone later down the road. If actual experience is not available or if the experiences are too varied to provide a good estimation, then the project manager should work with the project team to make sure the time estimates are reasonable and account for all the variables. It is much better to overestimate at the beginning rather than underestimate. Throughout the project, the time estimations should be evaluated and changed as needed in order to make sure the project schedule is useful to the team and the stakeholders throughout the project lifecycle.
Once the scope estimation and time estimation have been accounted for, the schedule can be fleshed out. One important part of the schedule to be included, that will help make the project a success, is the milestone events of the project. These events may be the end of certain phases or the point in time where work needs to be completed by. These milestones and how the team measures them will help the project manager stay on top of the key events of the project by managing the schedule. Pouring over hundreds of tasks each week can be daunting. The milestones help put the entire project into perspective and keep everyone on track for the successful finish of the project.