Be at any level of the organization, never accept back-to-back calls or meetings. Calls and meetings are not rituals. They are steps with follow-ups. So after every call or meeting, take a break of 15 minutes to recollect whatever we discussed and script an action plan on those.
The same way, before every call or meeting, take a 15 minutes prep time. This will help us to ask more focused and productive questions.
So eventually there should be 30 minutes gap between two calls or meetings.