You will already have discussed a clear strategy for your plea with your lawyer.
How is you case going to be presented? What documents do you need to provide for your lawyers?
What Psychologist or Psychiatrist will be providing a report? Will they also be attending to give evidence?
This is where all the work that you and your lawyers have done comes together. Character witnesses need to be checked and run through the process of what questions they will be asked. All your reports need to be got together and assessments made about what will be relied on before the Court.