What is the The Primary-Key(s) to develop a successfully Software/App?

1- Study the business rules and policies of the organization

2- Study the current case to find the GAP (Detremine the problem).

3- Identify the suitable solution as a template.

4- apply the concept: PDCA (Plan - Do - Check - Act)

5- Generalize the solution.

Detailed requirements specifications and staged development to reassess requirements with each delivery.

Need to balance between the security requirements and the functionality requirements. Also, need to consider deploying the security features from the beginning of the project.

It must be useful, its form should be an eye-catcher, and it should have the potential to reach the largest spectrum of the masses (snow-ball effect).