Hands on, mentally visualising the subject as well as orally presenting it to students. Mini end of session tests and a score to review that unit covered. These presentations not only increase chances of retaining the subject but also make it more interesting for them to be engaged throughout the session, not just the beginning and end.
At 30 mins we take a short 5 min break to give ourselves rest and reset for the 2nd half of the session. I recommend going for a walk for an activity away from screens to increase interest in subject at hand.
Experience all the way up to A level biology after completing my AS level in 6th form, with a final grade of A.