The recipe for a good scripted test case

Use appropriate TMS
Analyze your Test Strategy
1. Think about constraints
  1. Time
  2. Available recurses
Use Test Design Techniques
1. Black Box Testing Techniques
  1. Equivalence Class Testing
  2. Boundary Value Testing
  3. Pairwise Testing
  4. Decision Table Testing
  5. State-Transition Testing
  6. Domain Analysis Testing
  7. Use Case Testing
2. White Box Testing Techniques
  1. Control Flow Testing
  2. Data Flow Testing
3. Experience-based: Error guessing
Use Heuristics and Mnemonics
1. Use Testing heuristics
2. Use Testing Mnemonics
Use Matrixes
1. Use the Risk Matrix
2. Use the interconnection of components matrix
3. Use plarfotms Matrix
Create Test Case as soon as possible
1. Сreate the main scenario test case at the planning stage of the US
2. Сreate acceptance test cases right after planning, when the developers are just starting to work
3. Create test cases for US testing right after QC planning
Use shared steps
1. Cheet-lists for typical filds (Text, Date, Time, etc)
2. Cheet-lists for Injections (SQL, XSS,...)
3. Cheet-list for nonfunctional testing of Mobile Apps
4. Precondition steps
5. Your Product Scenario steps
Use Parameterization
1. List of Login/Password
2. List of servers adreses
Discuss the test case with programmers and analysts