Don’t just vary your shot size: use different camera angles and positions as well.
Instead of shooting everything from eye level, with the camera horizontal, try shooting with it pointing up or down. Crouch down below the subject, hold the camera above your head, climb stairs or use a tall tripod or ladder. If your camera has a swivelling screen you can use that to monitor the shot while the camera is in unusual positions. A remote control is also useful to start and stop shooting when the camera is out of reach.
You should also shoot from different positions around the subject, not just from directly in front or from the side. If they are moving, try shooting from in front and then from behind then editing the shots together.
But to make sure that shots from different camera positions work together, you need to follow a few ‘rules’.
Different camera positions can help tell your story
Shoot from above or below, as well as from eye level
Film from different positions around the subject as well
Make sure your presenter or actors are looking in the right direction