Having a good strategy scores 1/10 on the useful meter, the other 9/10 are allocated for implementation, adjustment, and learning.
That is not to down-play the difficulty of developing a good strategy, and the crucial value of such an investment of resources, it is time consuming, demanding, and usually highly iterative, combining both data and judgment in ways that deliver a competitive advantage.
However, no matter how smart the strategy, the key to success is the implementation. I wonder how many great strategies have been developed, bound, and presented, only to grace the shelf, pristine in its pride of place.
There are many tools to assist the development process, SWOT, Porters 5 forces, Balanced Scorecard, and many others, but the number of tools available has had little impact on the quality of the implementation process in most businesses.
However, the key to strategic success is to be determined to implement and measure the effectiveness of the implementation of strategic decisions taken, and being prepared to make alterations as new information emerges, or competitive conditions change.