Form a small team of people to work on the problem. Ideally, their knowledge and skills will be complementary, to give a broad but expert group. If it has not been already defined, meet first to define the key symptom or effect of the problem under scrutiny. Aim for a brief, clear phrase which describes what is happening to what, such as, 'Low sales of MkII Costor'.
Make sure that only a single effect is described, as this may result in several sets of causes. For example, an effect of 'damp and dirty conditions' could have different causes of dampness and of dirt.