Principles are a great tool with which to document difficult decisions during strategy development. A principle is a belief of an organisation. It can be documented as a simple statement or as a page capturing the description, rationale, implications and dependencies (if appropriate).A Principle can be developed when it is more important that a decision be made rather than what the decision actually is. This can be used at any stage in the development of a strategy. Only a few Principles will be developed; you hope. They are good for resolving technical arguments between opposing camps in a large organisation.
Also, sets of Principles can be used to link business goals to the IT strategy. This linkage can be explicitly documented by creating a pair of spreadsheet tables:
Documented business goals against IT Principles.
IT Principles against IT strategy elements.
The set of Principles and the linkage tables become part of the IT Strategy document.
In both situations, the Principles are developed in a facilitated workshop environment with the clients technical and business stakeholders.