Stephen Covey in his now famous book, "The Seven Habits of Highly Effective People", introduced the habit of begin with the end in mind. I've been applying Covey's ideas to all aspects of my life for some years and they were also an inspiration for one of the two podcast series I produce called quite naturally, Life Habits. I've also been of the view for some years that many of Covey's habits apply directly to the practice of design but the one that is most relevant is begin with the end in mind.
These was a trend some years ago which advocated starting a software development project by writing the user manual first. While an interesting idea from some perspectives, I always thought that this didn't go far enough. I advocated and still do that the first thing that should be designed in the advertisement.
The advertisement, if done correctly, clearly communicates the benefit the user will gain and/or the business value a company will realize if the product is purchased and used. Furthermore, the advertisement should communicate how the benefit/business value will be realized. This information should become the vision document and the highest level objectives for the design.
As in life, if you start your design with the end in mind, you're much more likely to achieve it.