Initial Ideas

My first ideas are that i want to create a Pyschological thriller involving One main characther, and the whole story line is based around her and a crime that she has commited, although only she knows that she has commited this crime, which my first initial idea would be she had commited Murder. I am going to use the one main character, however i would like to use split screen effects to have the same character shown twice like her concious is following her. As i collect togetether ideas i am going to then Build up my story board. I know i would like the trailer to begin with a close up of the main characters face, and then the ending will consist of quick montage edditing, also the shots will have Inter titles between some of the shots.