The customer's (client's, patient's) initial response to a marketing message is, "I don't believe you!"
When we say "but", it's like crossing out everything that we say in front of it.
How much you can or should invest in marketing is primarily a numbers game. Instead of thinking "how can we minimize marketing costs?", think "what marketing costs are necessary to dominate our market or to generate a desired level of profitability?"
A very common mistake in sales presentations and business communications is to take the viewpoint of "I" or "we" (the company), instead of "you" (the customer.)
A reader's name will always get their attention
A Unique Selling Proposition can stop qualified customers in their tracks.