In today's world it is very hard if not impossible, to actually create something completely original (and worth watching). I red somewhere (don't remember where exactly, though) a phrase that really struck home with me, leaving a huge impression : "Every story possible has been told at least a thousand times. The point isn't telling something new - that's impossible. The point is telling it better than the other thousand guys.". Honestly? I find this largely true. Just look at movies, books, comics, etc.... How often do you see anything new? Don't answer that - it's a very rare occasion. Very, very rare.
OK, you have an idea. Sadly I'm about 90% sure that somewhere, someone has the same thought as you . So what IS your job as an author then? Why, doing it better than the other guy of course! And to do that you need something more than a good story, more than good, fleshed out, believable characters, more than good overall writing (you do need all of them, though) - you need to know your tropes. What is a trope you ask? Well in short (taken form the great site tvtropes.org - more on it in a sec) :
Tropes are devices and conventions that a writer can reasonably rely on as being present in the audience members' minds and expectations. On the whole, tropes are not cliches. The word cliched means "stereotyped and trite." In other words, dull and uninteresting. We are not looking for dull and uninteresting entries. We are here to recognize tropes and play with them, not to make fun of them.
Using, playing with and averting tropes is a very important skill - one valuable for every author I can imagine. It gives you the tools you need to play with your readers expectations, avoid cliches and make an overall better story.
Free advertising time! I took the liberty of quoting tvtropes.org - a great wiki type site that deals with exactly this - tropes in fiction. It is a huge time sink - but in a good way! It's very amusing and informative - honestly I don't know why anybody who has any interest in fiction wouldn't read it. I'm sure you'll find it very useful.
P.S. Sorry for the radio silence these days guys, but the holidays make fools of us all. I promise I'll make it up to you next year. Meanwhile enjoy what I have, comment if you can - criticism aways accepted. I hope you have the greatest holidays! Cheers.