Find the right questions

Replace the words in brackets with marketing/marketeer, design/designer, or with almost any other profession, and the quote below will be just as applicable.
"The best [petrographic] examination is the one that finds the right questions and answers them with maximum economy in minimum time, with a demonstration clear to all concerned that the right questions were answered with all necessary and no superfluous detail. In practices the approach to the ideal varies depending on the problem, the skill with which the questions were asked, and the skill of the [petrographer]. One measure of the [petrographer]'s skill is knowing when to stop, either because the problem is adequately solved, or, in some cases, because it has been shown to be insoluble under the circumstances."
Katherine Mather, 1966, Petrographic Examination. Significance of Tests and Properties of Concrete and Concrete Making Materials, ASTM Special Technical Publication No. 169-A