This article and the comments provide a very useful overview of the importance of strategy for any organisation, and a discussion of the difficulties in professional associations. To this I would add two things. First, a strategy has no focus unless it is in pursuance of clear and explicit aims, or mission or vision (call it what you will – it is the answer to the questions “Why does this association exist? What are we all trying to achieve here? If we succeed what will be better about the world and specifically our common domain of interest?”)
Second, the leaders and future leaders within the organisation need to become highly skilled in leadership, and developed as a team to work together and drive change.
My own experience of developing strategy, in public organisations, local authorities, publishing companies and policy settings, chimes with the steps outlined by Michael Clarke but with those additional points addressed beforehand.