Before the lesson
Ask for the topic, exam board and any recent work. Test your connection and screen sharing a few minutes early.
The first ten minutes
Say hello, then ask the student to show you something they found hard. Listen to how they explain it. This tells you where to start.
The middle
Teach one thing well. Let the student try a problem while you watch, then step in only where they get stuck.
The end
Summarise what was learned, set a small piece of practice, and agree when you will meet next. Finishing with a plan is what turns a trial into regular lessons.