Planning concerns knowing what you want to achieve but as yet not knowing how to get there.
It usually begins with devising various strategies, assessing them and then choosing one of the options to go with.
At this point, you have, in effect, cut all ties with the other options.
If you choose incorrectly it can be prove very costly.
It is for this reason that you must consider where the key problem areas can occur and create contingency plans that you can implement if necessary upon a particular trigger. Drawing up contingencies is all about reducing risks in planning and this is discussed in much more detail in 'The Complete Risk Management package'.
Ultimately, you need to plan for the preparation of your schedule to have any idea of where you are going.
Any progress is then gauged by comparison of an earlier baselined schedule with the current one.
Without the project schedule you cannot track progress.