I make a strong effort to keep my focus time sacred. If someone schedules a meeting during focus time, I'll often ask to reschedule or be left out of the meeting.

Emergencies are emergencies. If there's an incident, of course I'm available to help. But I also have a lot of trust in my team. The on-call engineer can usually handle any incident and there are other senior engineers around to help, not just me.

For advice seekers, I try to use a system of office hours at a set time (usually right after standup). Or, we schedule a pairing session for a set time on the calendar that doesn't interrupt focus time.