what makes a good film poster?

In my opinion i think what makes good film poster includes clear information, the title should be bold so it is eye catching and relates to the film genre. Example: if the genre of the film is horror, therefore the title has blood all over it to represent the genre. it should have a colour background that is related the genre. example: if the genre of the film is horror, the background colour should either be red or black. the film poster should include the basic things such as release date of the film, the age rating, credit block and film company.