Thriller Conventions

Thriller films stick to several conventions that define the genre. These make it easy to tell that it is a thriller, these often get confused with horrors but there are a few main differences.

Conventions of a thriller:
Music:
The soundtrack is usually quite subtle but constantly tense and keeps the mood of the film serious and keeps the audience engaged.
The instruments used are usually orchestral and are kept to a minimal score.

Lighting/Camerawork
The sets are usually very dimly lit and this is because of the use of low-key lighting and dingy locations.
The camerawork is all low level and kept below or at eye hight this gives a effect of being there or on the same level as the main characters, this keeps you involved on the characters level.

The Set
Thrillers are usually set in a city or urban location this also gives the effect of a never sleeping set where anything can happen at any time.  The grungy location also ad to the sad or depressing feeling of the film. The sets are usually very dark and dusty, this helps you feel for the characters as you would not like to be there yourself.

Narrative
The narrative in thrillers usually slowly builds tension and creates an air of discontent that make you want to know what happens at the end, and this gives time for the characters to grow on you and by the end you feel strongly for the characters and this creates a better feel when, eventually, the film comes to a happy (or sad) conclusion.

Characters
In thrillers there is always a antagonist and a protagonist, the antagonist usually has a weakness that is exploited by the protagonist, this is often hinted at by the title.