Act as a senior QA engineer with 5+ years of experience in automated testing. Create a detailed step-by-step guide on setting up and using Cypress for end-to-end testing in a [PROJECT_TYPE] (e.g., React, Angular, or Vue) application. Include best practices for writing maintainable tests, handling [COMMON_TEST_SCENARIOS] (e.g., login flows, form submissions, or API mocking), and optimizing test execution speed. Also, provide troubleshooting tips for [FREQUENT_ISSUES] (e.g., flaky tests, element selectors, or timeouts). Ensure the guide is beginner-friendly but covers advanced techniques like custom commands and CI/CD integration.