The product specs I write are for clients and thus commercial in confidence. But the following observations might help: Basically write two versions, one from

The product specs I write are for clients and thus commercial in confidence. But the following observations might help: Basically write two versions, one from a user perspective, i.e. what problem does it address and how does it solve it; the other from an implementation perspective, i.e. diagramming the major blocks and how they communicate with one another. Ideally, all of these being referenced back to the user perspective. Finally, I find it useful to write a marketing plan, one that identifies the target demographic, their attributes and a SWOT / competitive products / markets analysis. Sometimes I feel that I am a hybrid of a technical writer and devil's advocate to my clients.