When you watch a scary film, there will be many different parts that will determine its success. The first obvious key point is that a scary film must be scary. This may sound ridiculously simple, but attempting to cash in on the success of Japanese horror films, the American remakes lack any of the tension, drama or fear of the originals.

To make a scary film is a very difficult task. The music must be good, acting is important (to an extent), and the setting is probably one of the key components to a really scary film. The scariest films base fear on tension and unease, rather than obvious and gratuitous violence and horror.

To succeed as a scary film, the viewer must be drawn into the film's world and feel a certain level of worry as they watch. This concept was explored brilliantly by The Blair Witch Project (1999). The film uses viewer interpretation to increase suspense during several important parts of the plot, including the finale.

The film is shot using a handheld camera, mixing colour with black and white, making the film seem more realistic and documentary-like. The characters seem like genuine people, with the low-budget also helping the film to be as unsettling as possible. Viewers will find themselves sympathetic to the plight of the film's characters, and feeling the fear and horror as the story unfolds.

Possibly the most important scary film of all time was released in 1973 when William Friedkin directed The Exorcist. Based on the novel by William Peter Blatty, The Exorcist would go on gross over four hundred million dollars amidst a blaze of publicity and controversy.

The film arrived with stories of on-set incidents and the movie being cursed, further fueling the controversy. With several injuries suffered to actors and film-staff, the film also suffered at the hands of the British censors when it was withdrawn from video release in the 1980s.

The Exorcist is an extreme film with every part of it testing the audience's resolve. The plot is unforgiving, as is the language and the music, forcing a reaction that can range from disgust to panic. A resounding success as a horror film and one of the scariest movies ever made.

Isolation and hopelessness can make a film as scary as the obvious fear attached to more conventional horror films. Where some people find slasher films scary, the atmosphere and tension associated with slower-paced psychological films can be far more devastating to watch.

The most impressive psychological chiller to grace the silver screen is the Stanley Kubrick directed The Shining. Based, very loosely, on the novel by Stephen King, The Shining avoids becoming sloppy, cheesy nonsense - a fate that many King adaptations seem destined to achieve.

A father, mother and son spend the winter in a secluded snowbound hotel so that the father can concentrate on writing a novel. The haunting music and beautiful scenery contrast dramatically, as does the performance of Jack Nicholson as the disturbed and manic father with the solitude and calm of the location.

Kubrick works masterfully with the movie, even more-so if you watch the King-endorsed 1997 TV movie. King didn't enjoy the 1980 classic, probably a good thing as most horror fans will appreciate his work as a writer but note his ventures into movies are generally weak and diluted.

There are many films that can be considered as scary, including the classic movies The Silence of the Lambs, Texas Chainsaw Massacre and Psycho. These all deserve a mention, as do slasher movies such as Halloween, A Nightmare on Elm Street and Friday 13th. With such a selection of fantastic films to choose from, it's hard to narrow the most influential down to just a few.