Be transparent in how you pad estimates. This builds trust with stakeholders so that when things go awry, you can remind them.
Require anyone who reports to you during the planning process to do the same; provide the most accurate estimate possible, then be transparent about their padding.
If there's a a 'known unknown' call it out. Mitigate risk with high-level executive check-ins. Be candid with your status lights, and tell them what you're doing to mitigate any risk on a regular basis.
Migration is about managing up to the org not just to a boss; the more candid you are the more you deflate the rage that comes with unexpected downtime, rollbacks, etc.
Require anyone who reports to you during the planning process to do the same; provide the most accurate estimate possible, then be transparent about their padding.
If there's a a 'known unknown' call it out. Mitigate risk with high-level executive check-ins. Be candid with your status lights, and tell them what you're doing to mitigate any risk on a regular basis.
Migration is about managing up to the org not just to a boss; the more candid you are the more you deflate the rage that comes with unexpected downtime, rollbacks, etc.