You must show that you were terminated based on an illegal reason.  In a wrongful termination matter you have to show you were terminated because of your status such as being physically disabled or because of your religion or your gender or pregnancy or another protected status.  Or, you need to show you were terminated because you asked for payment of your wages or other wage and hour rights.  You can prove your case in a wage and hour case often with your own testimony plus your wage statements, schedules, texts between you and the employer or other evidence such as time punch cards.  In discrimination cases you can testify about statements that were made to you or others about your disability for example.  Or you can use a pattern of behavior as evidence such as all workers over 40 were terminated while all younger workers kept their jobs.  There are many ways to prove a case.  Your lawyer will help you by evaluating and presenting the evidence.