Hierarchical Task Analysis is an excellent method of capturing how tasks are performed in a systematic and structured fashion. It is a graphical technique that allows groups to work on the analysis together. This is useful for identifying different practices and for developing a consensus on what constitutes best practice.
Hierarchical Task Analysis is particularly useful when developing procedures, training plans and competency systems. Also, being hierarchical it is particularly suited to new projects as it can be developed in conjunction with the design.
This article titled Task Risk Management will give you a context in which HTA is particularly valuable. The following video clips should you how to carry out HTA in practice.