Developing agile enables rapid application development if all requirements are understood and documented before starting for the web application development project. Hence to reach an agile-able state there are a lots of prerequisites that need to understood and documented before the Agile sprint can be started:
Here is a process diagram that can be implemented to enable the rapid application development.
As you see that there are input documents for each phase of software development. Before the project starts most important being the Requirement Analysis. Requirement analysis accurately documents all necessary features in details and functionality desired. In web applications this is not enough because additionally a visual design is necessary to create how the app will actually be used by end user. The mock-up of all the pages and visual design gives a clear flow of the app.
Based on the visual design and requirements documentation its now possible to create a Product Test Plan. This test plan is actually used by the Tester/QA to start with Test Case development. As shown the Tester/QA engineer develops the Use Case document so all Test scenarios can be developed. All these documents are input documents for Detailed Technical Design document.
A detailed technical document is then reviewed and approved by all stakeholders. An Agile Scrum master is now ready to take this forward since all the detailed technical design and the tasks can be identified. Scrum Master then proceeds with a 10 day sprint cycle and delivers a demo at end of each sprint.