Genre

Horror: Horror films are interesting in the way that there is very little grey area for 'decent' or 'ok' films. They are usually terrifying, or hillariously awful.
Horror films can create unease amongst the audience with use of intense non digetic sound, an example of this would be the shower scene from 'Psycho' where the violins screetch louder as the killer approaches.
 Another exmple (although not a horror film) would be 'JAWS' where the iconic 'creeping up' styled music is played as the shark approaches.

 Close up and extreme close up shots of the victims in peril are often used in horror films to increase the intensity of the scene, tied in with rapid shot change this can be very effective in subtly putting the audience on edge.

Horror films are often stereotypical in the way that they portray the fear of the film, props like fake blood can add a sense of fear, however when overused it can completely take away from the effect that it creates and often make the film look rediculous. In the popular film series 'SAW' there is potential for the film to be quite thrilling but with the over use of blood the films are now often rediculed for their mise en scene

Romcom: Romantic comedy films or 'romcoms' help portray their often light hearted nature by utilising slow camera movements to create a romantic attmosphere. Romcoms often follow classic stereotypes such as:
one of the characters giving up their life long dream to be with the person they love. In reality this decision would be much harder to make and couldn't be done spontaniously in an airport or train station. This can often make the film predictable as we pretty much know that the couple will end up together.
Examples:
'how to lose a guy in 10 days'
'going the distance'
'the family man'

Another cliche that is used in romantic comedies is, two characters get along so well that they never even notice the right person for them has been there all along (often because one of them is already attached).
Examples of this would be:
'When Harry Met Sally'
'The Wedding Singer'
 'Made of Honor'

Comedy: Comedy films often follow similar stereotypes and cliches, a classic example of this would be the division of groups in a high school environment. Athletic boys are portrayed as the villain of the film as they cause massive inconvinience for the protagonist. In the film 'Dude Where's My Car?' the two main characters, Jesse and Chester's aim of talking to attractive girls is always cut short by Tommy, a pumped up football player who constantly harasses them, this type of character always seems to get his comeuppance at the end of the film.
Another stereotype used in comedy films is that everything goes wrong in the third quarter of the film before everything is resolved in the final quarter of the film. An example of this would be in the film 'Role Models' where the two main characters (who have to complete community service with children) are deprived from seeing the children after they offend their parents. This is soon resolved before the epic battle intthe final segment of the film.