In every school, there is at least one nerd or wimp that is shoved into lockers that are big enough to hold them. High Schools are always either in the middle of a city or a car ride away from the beach. All beds have a special L-shaped top sheet, which reaches up to armpit level on women but only to waist level on men. No-one ever needs a kleenex after sex. If you're a woman in a film and have just finished a steamy lovemaking session, make sure to lay back and pull the sheets up to your neck, just like in real life.
All women moan during sex, but none sweat.
Bags of groceries are never heavy. Whenever anyone in a movie goes shopping, they always come back with stuff sticking out of the top of the shopping bag, usually carrot tops and French bread. If the tapping sound or flashing light represents morse code, there's always someone around that can interpret the message. When Morse Code is used, the interpreter will call out words as they are being sent, rather than letters. You got plenty of time up there, often a couple of minutes.