Conventions of Genre

What I hope to go for is crime or thriller. I have been noting down different genre conventions especially by watching movies and noticing the different shots, lighting, movements and especially the editing. I have noticed in crime or thriller movies, the opening usually tends to be fast paced, or very suspenseful, introducing a suspenseful character leaving the audience to wonder what will happen. The lighting is usually grey or light. However, in certain crime movies there is a ray of comedy found which tends to make the scene lighter and the audience captivated.