Web application testing is an important part of the software development life cycle. It ensures that the application functions as intended and meets the requirements of the users. Here are some strategies for effective web application testing:

1. Requirements analysis: Start by analyzing the requirements of the application. This will help you understand the expected behavior and functionalities of the application, and identify the areas that need to be tested.

2. Test planning: Create a test plan that outlines the scope, objectives, and approach of the testing process. Determine the types of testing that need to be performed, such as functional testing, performance testing, security testing, etc.

3. Test case development: Develop test cases that cover all the functionalities and features of the application. Test cases should be clear, concise, and include both positive and negative scenarios.

4. Functional testing: Start with functional testing, which verifies that the application functions as intended. This includes testing the user interfaces, navigation, forms, database interactions, etc.

5. Regression testing: Perform regression testing after each new feature or change is implemented to ensure that the existing functionalities have not been affected. This includes re-running previously executed test cases to validate the overall system.

6. Performance testing: Test the performance of the application under different scenarios, such as high user loads, peak traffic times, etc. This includes testing the response time, scalability, and stability of the application.

7. Security testing: Test the application for vulnerabilities and weaknesses that could be exploited by hackers. This includes testing for authentication and authorization issues, data encryption, secure transmission, etc.

8. Compatibility testing: Test the application on different browsers, operating systems, and devices to ensure compatibility and functionality across multiple platforms.

9. Usability testing: Test the application from the end user’s perspective to validate its usability and user experience. This includes testing the ease of navigation, clarity of instructions, responsiveness, etc.

10. Error handling and recovery testing: Test the application’s error handling capabilities and recovery mechanisms. This includes testing how the application handles errors, displays error messages, and recovers from failures.

11. Automation testing: Consider automating repetitive and time-consuming tests using automation tools. Automation can help increase the test coverage, speed up the testing process, and reduce human errors.

12. Continuous testing: Implement continuous testing practices to test the application continuously throughout the development process. This includes integrating testing into the continuous integration and delivery pipeline, and automating the testing process.

Overall, effective web application testing requires a combination of different testing techniques and strategies. By following a systematic and comprehensive approach, you can ensure that your web application is of high quality and meets the requirements of the users.