I'm not a fan of project scheduling tools. I have trouble making the tools create the schedule the way I think, and I can never quite see the whole schedule when it's in electronic form. Other people, especially senior managers, tend to believe the project schedule once it's in electronic form, no matter how outrageous the schedule is. Since I mostly work on iterative or adaptive projects, I don't normally have to use scheduling tools because I'm scheduling small pieces at a time. But when I teach project management or perform assessments, I work with people who are accustomed to using project scheduling tools. And, something that surprised me, they use the project scheduling tools from the beginning of the project to lay out the schedule.
As I was finishing this rev of my Pragmatic Project Management workshop, I realized why I like yellow-sticky scheduling (especially at the beginning of the project) so much. Yellow sticky scheduling, where you lay out the tasks on yellow stickies, one task per sticky, allow you to treat the schedule as if it's a design. Yellow stickies help you see a prototype of a schedule. You can use a whole wall and see the “complete” (as much as you're willing to deal with) schedule for a large project. The schedule isn't in electronic form, where it's not only harder to modify, you treat the schedule as if it's something more real than it is.
The project schedule, especially at the beginning of the project, is a promise on the part of the project team to try to meet their estimates/guesses. The only thing you know about the project schedule is that the way you've laid it out is the one way it won't happen. Life happens and the project schedule can't reflect the server going down, the thunderstorm that took out power in one sub-project's building, or the person who had an emergency appendectomy. All those events happen on projects, and you can't know at the beginning when you schedule a project what will happen. The schedule is how you hope the project will unfold — but it's certainly no guarantee.
So prototype your schedules, as you would designs. I like yellow stickies, but you can use index cards, or even large whiteboards, as long as your materials allow you to easily move tasks around and see how else to organize the project. Seeing the project laid out on a wall will help you see potential problems in the project or alternative designs for your project. Once you can see the whole project, you can anticipate problems and risks. Stay away from high-tech scheduling tools as long as possible. The lower-tech your scheduling, the more likely you can see problems in your projects.