First be Agile, then aim for Continuous Delivery.
Big rocks first!
Infrastructure, project management, processes, people and culture comes first.
Then pebbles and sand around.
Continuous Delivery mindset is more important than the tools makes it happen.
Prioritisation of the steps to be taken is quite important in order to win. You need to know your direction before you want to start a DevOps initiative. Because it's important, time consuming, difficult and people resist to change.