1. To know negative or positive test cases first you need to know the scenarios. 2. To know negative scenarios you need to know the validations on various fields. 3. Depending on validations, choose a test design techniques to decide on the data that you are going to use while testing. 4. Form combinations on this data. 5. Rank the combinations. 6. Select the combinations for testing. 7. Write the test cases. Example: Login Screen. 1. It has two fields: ID & Password. 2. ID has to be valid employee ID (numeric) and password has to be matched with a stored one. 3. User can click on Cancel if wants to discontinue. Upon clicking on Cancel the application closes. (In case web application either browser closes or the tab closes.) 4. Upon clicking on Forgot Password link another form gets displayed. 5. Upon successful login, user gains the access of system. 6. Upon 3 consecutive unsuccessful attempts the User gets blocked, user gets appropriate message and u...