Use appropriate methods (Agile vs Lean vs 6 sigma)
Try to avoid the tyranny of one — there is no single, magic solution. In any large organisation you will have to use multiple methods at the same time. PowerMaps enable you to understand context and which methods are (and are not) appropriate where.
For example, on the left of a PowerMap, where components are new and unstable, your focus should be on reducing the cost of inevitable changes. Agile is great for this — rapidly iterating the uncertain as you try to make it viable. But as your new 'thing' evolves and moves further to the right it becomes more certain and stable and Agile is no longer as useful (and can even be dangerous). On the right of a PowerMaps components require methods like Six Sigma (or outsourcing) that focus on reducing deviation in performance (think power supply — you definitely don't want to "Agile" that). As components transition from left to right they also need other methods, like Lean, which focus on the learning required for continuous improvements.
Be mindful of ego here though — tribes can form with almost religious fervour about the righteousness of their method. Have fortitude, as you'll often find you're arguing against all these tribes at the same time.