Intentions for our film

Because we're doing a slasher film there are obviously some props, characters and other things that we feel that we have to include:
A killer
A weapon - mainly a stabbing implement
Some creepy music - to suggest stalking
But we would also like to include a few other things that we think will make our opening make more sense and a bit more scary:
A child's toy
An old caravan
A mask - which could also be something compulsory that we need to include in our film.