If not done thoughtfully, it can take years (forever) to dig out.
Spend time with the employees. Learn their names and stories.
Meet customers. Talk about continuity of service, importance of respecting past practices.
Be Very careful about making promises.
You want to validate your pre-closing diligence and address any key misses.
You want to save any customers that might use the transition as a reason to leave.
I've found it helpful to sketch out a plan pre-close and then adapt as I dive in.