A specification is written to solve a problem of some kind. It is surprisingly often that people try to write a specification without fully understanding the p

A specification is written to solve a problem of some kind. It is surprisingly often that people try to write a specification without fully understanding the problem - the steps are Problem Identification, Requirements Capture, Specification. This is especially the case with user requests, they often don't specify the problem in their request, but provide their desired solution, which may not be optimal across the system, or may not have considered all the possible options at the right level. The requirements should solve the problem, and the specification should address the requirements. If you break it down in this way then is can become easier. On large conventional engineering projects as much as 15% can be spent on these first phases, and then a decision made whether to fund or not.