Deciding a strategy
The strategy depends on the situation.
Working on large projects (or Programmes) with strong management can somewhat determine the strategy for you because of the need to fit in with timescales for delivery and the need to follow a standard textbook approach of Stakeholder Analysis, Change Impact Assessments, a communication and engagement strategy and Training Plan.
For everything else, or if a large project is looking at the changes more deeply, understanding who’s impacted and how, at least broadly, can completely change the path taken.
Thinking through a strategy involves envisioning the future and working backwards over how to get there, taking into account how soon you want to achieve it and then considering the work needs to be done to prepare and how much time is needed for it.
Having a strategy can also be a luxury - if Change Management hasn’t been possible and if any issues have arisen, fire fighting them is also a strategy.