Shoot your film in order as much as possible. (time saving)
Shoot the same scene from multiple angles. For example someone approaching and opening the door from the outside, then the inside.
Keep the camera steady. Use a tripod or steady against something.
Record 5 seconds before and after the shot you want.
Take a setup shot to establish the setting. For example if you are taking an indoor shot of a school, first show the audience an exterior shot so we know it is a school. You can show more than one shot, like the school, then the flag.
Shoot very short segments and plan and rehearse your audio.