Some related points are made in Guerrilla Marketing for Consultants, an excellent book by Jay Levinson and Michael McLaughlin. (If you haven't got a copy, you might want to get one.)
The thrust of the book is that traditional marketing methods can be ineffective in today's world, because so much sales effort over the last century has built up resistance.
For example, go to many websites of service companies, and you'll see the same old claims being made, with minor variations:
According to the authors, that's all "safe" – but being safe can end up with your being sorry.
Another common trend you'll find on websites and other marketing material, even from companies that should know better, is a focus on themselves, their people, their services. (Some of them talk about themselves in the third person, which is even more of a turn-off.)
Levinson and McLaughlin rightly point out that it's far better to focus on the clients and their issues; bragging about your own success and prestige is hardly the way to win clients and influence people.
They talk about directing your marketing effort according to your target groups, and suggest 60% goes on existing clients, 30% on prospective clients and 10% on the wider market.
Their recipe for effective marketing is to turn the traditional bombardment approach on its head. Instead, they say, better results will come from listening to the client's needs, asking insightful questions – and only then delivering solutions that are directly tailored to those needs. The days of one size fits all are surely over.
There is a lot more in the book that repays attention. But I'd like to finish with a quote that the authors use, from Henry J. Kaiser: "When your work speaks for itself, don't interrupt."