Execution requires behavioural change, which is one of the hardest things to generate. The greatest enemy of change is the day-to-day activities just to keep things running. The urgent but not important.
Delivery involves translating planning and thinking to execution and involves two levels – ‘what’ has to be achieved and ‘how’ to achieve the results.
The 4 Disciplines of Execution explains how to actually get the things in the plans done.