Several things should be clear early on.
First (and this whole chapter reflects this fact). the success of direct mail is in the detail. Thus it needs some care, and respect for the proven principles, to get it right. Attention needs to be given to all aspects of it, from creating a well composed persuasive letter to having the right kind of short message on the envelope.
Secondly, direct mail is only as good as the list that directs it. A list is an asset to be nurtured, updated and refined. Address those on it you kn ow best accurately and maintain correct details, for they are likely to be the best respondents.
Finally, although it is not something to panic about, there are controls and laws of data protection need to be known and respected.
Get it right, however, and direct mail is a technique that can work well and profitably.
Reference: Direct Marketing In a Week: Patrick Forsyth