A few months ago, I was asked to distil business writing skills into a 30-minute presentation followed by lots of practice. The delegates were managers and team leaders in a large British company. (Not IT or environment, as it happens.)
After much deliberation - cutting is so much harder than adding, I got the presentation down to a core of nine slides:
You can get it/download it from SlideShare.
Hopefully, you'll find the tips helpful but, if you want more, please drop me a line - my name [at] tebbo.com is easiest.