Have a good (i.e. not vague) one.
Develop a Personal Mission Statement. Really clarify. Develop a statement of purpose that’s actually useful. Don’t use vague, meaningless statements. You could also call the items on there your Guiding Principles.
The more specific, the better. Don’t say “I will be courageous and fair”, say “I will not avoid bold options and I will always seek to understand both sides“. Also, when possible, the more plainly stated they can be made the better.