It sounds obvious but one of the ways I have been successful when working with senior people is to do my homework and find out a detailed analysis of their workforce.
Spend some time with HR and CIO learning about the audience profile. What are their ages, career levels, and typical roles? Where they are located, and what comms devices do they have access to? (iPad, smart phone, email, voicemail.) What are their habits?
This helps add some gravitas to pitching ideas or advising on the best tools to use when approaching a communications problem.
Internal Communications Manager, Accenture