Matthew Branton, who has four internationally published thrillers to his name, argues that thrillers are about escalating stories: they put something at stake, and then they raise the stakes. If you are going to write thrillers, you will have to develop plot ideas in which your hero character needs to achieve something, but a series of escalating problems contrive to prevent him.
So first you need a hero or heroine. This main character can be anything from a super-performer such as James Bond to an ordinary bloke who finds himself having to draw on internal resources he never knew he had. And what they need to achieve can range from saving humankind from extinction to getting Aunt Doris off a train that is going to explode. And as the hero goes about achieving the aim, the problems blocking him become increasingly dire.
Mr Branton’s book explores the techniques of characterisation, structure, tension, conflict, dialogue and much more that you will need to write thriller material.