The "Minto Pyramid Principle" looks interesting, unfortunately it appears to be out of print ($60+ on Amazon) do you have any recommendations for similar, perhaps cheaper books?
http://www.gazhoo.com/upload/document/2011/05/07/20110507170...
http://rtphoto.co.uk/tomflaherty/pyramid.pdf#best-memo-youll...
The answer is: sitcom + question = Answer.
Situation (We need to)
Complication (But ...)
Question (So how / what / when / where / can / could ...)
Answer (This is what you want from them).
I think there's a lot of other good communication advice in it, but most looks pretty generic (cut out the crap, use appropriate language, have some structure, etc). You've read Strunk and White right?
(Note, I've just scanned a summary, so that might not be all there is to it).