I have been asked to pull together a short workshop using 'real life' letters as 'bad' examples with a view to providing staff with good practice tips, etc, to enable them to communicate effectively with customers using the written word...

I work for a housing organisation, so, many of our letters are of a negative subject (e.g. rent arrears, anti-social behaviour, death, etc).

Help! Any exercises, tips, techniques, etc? We are a poor housing provider.... so the words of particular interest are 'free' and 'inexpensive'.
Ian Stone