The software testing life cycle consists of several phases: requirement analysis, test planning, test case development, environment setup, test execution, and test cycle closure. Each phase has specific activities and deliverables ensuring thorough testing coverage.

Manual testing involves human testers executing test cases without the use of tools, focusing on exploratory and usability testing. Automated testing uses scripts and tools to execute tests, ideal for regression, performance, and load testing due to its efficiency and repeatability.

First, I would gather all the necessary requirements and understand the application's purpose. Then, I would identify test scenarios, create test cases, set up the test environment, and execute tests. Finally, I would report defects and work closely with the development team to resolve issues.

I have utilized tools such as Selenium for web application testing, JUnit and TestNG for unit testing, Postman for API testing, and JMeter for performance testing. Each tool has its strengths depending on the testing requirements.

A test case is a detailed set of actions or steps to verify a particular functionality or feature of an application. It includes test inputs, execution conditions, and expected results to determine if the application behaves as expected.

Best practices include maintaining modular and reusable test scripts, prioritizing test scripts based on application modules’ criticality, using version control for test scripts, regularly updating test scripts to reflect application changes, and employing continuous integration for automated testing.