It depends on which level and business unit you are trying to move into. A graduate has to go through the program - the best thing I could say is be yourself if you don't match PwC criteria you DON'T want to be there.
Experienced - personality and experience take a sales based approach to your career detail how much benefit you have provided to the company or companies you worked for (putting it terms of money gained or saved is helpful).
How you manage your personal network, this can be more important than experience even if you aren't going into a sales role.
Soft skills - client, people management, it doesn't matter how or in what capacity retail sales project management etc.
Develop good technical knowledge in your field and have good communication skills
Know about PwC business and prepare accordingly. Know your job well.