To kickstart this, you should consider where your natural interests lie; which genre/s will you enjoy working on for the next few months? It won't necessarily be the case that you end up working within a genre that you are familiar with - it is also vital that your idea enables you to read up on and comment about conventions of a genre - but it won't do any harm!
So, a very simple task, leading on to a more demanding task...
(2) What was the last movie you paid to go and see in the cinema?
(3) What are your favourite TWO film genres?
(4) What are your all-time top FIVE films?
(5) Which ONE of these is your absolute favourite ... and why (be fairly detailed on why!)*
This will lead onto a task involving your screening the opening 2 mins of a film of your choice, explaining in detail what this tells us about the codes and conventions of (1) film openings in general and (2) the genre specifically...
*I'm sure you'll all agree with me (and Guardian writer John Moore) that Withnail and I is the best movie of all time! (It will shortly be arriving in the Library!)