Before I start to choose what the film will be about I first need to decide on what genre the film will be, below is some research on different genres.
Action
Action films are a good source of escapism, usually pitting one man against the odds. Actors who play a lead role in an action film usually play them for the rest of their career, they can also become icons and become instantly recognizable for some of their most famous roles, such as Bruce Willis know as John Mclane because of his role in Die Hard. Packed with gun fights, car chases and explosions Action films usually have a large budget but their massive popularity means that they easily get the money back in the cinema.
Horror
Horror films are supposed to unsettle the audience, different types of horror will try to do it in different ways for example some horror films will try and disgust the audience with gore while other with use jump scares keep the audience on the edge of their seats. Some contexts for horror films can be zombies, ghosts, demons and torture, these are used because they are things which frighten the audience. Horror is probably the most controversial genre as each on tries to push the boundaries to make in even scarier.
Thriller
While horror films deal with the supernatural, thriller films can feel very real. A thriller keeps people on the edge of their seats and uses suspense to keep them watching and waiting for the ending. There is usually a lot of mystery in thriller films, in some cases the main character has to find who a murder is before the murderer kills another victim, the excitement comes from being as clueless as the main character. In other thrillers it can be the main character put in a situation which no one can understand, in Phonebooth a man is held up in a phonebooth by a sniper, here the police is as much as a threat to the man as the sniper is, the audience can't see how the man will survive the situation creating a lot of suspense.
Comedy
A comedy films main attraction is its humour. Comedy films are usually feel good films and usually have happy endings, with the exception of black comedies, such as Fargo which despite the films context makes the audience laugh. Comedy comes in a wide range of different sub genres from slapstick to satire their is humour to be found in them all, some can be broad while others can be found on different levels, Ghostbusters is a great example of a comedy movie, kids enjoy the physical comedy, adults enjoy Bill Murray's dry humour, which is something a child may not understand.