Even the Bible says there’s nothing new under the sun, and that was quite a while ago. Generally creativity means the combination of existing elements to produce something different from either of them (and, ideally, more useful or interesting than either of them alone).
If you haven’t thought about it already, consider what experience you want people to have. One way to focus on this is to write the review quotes you’d like to see when your film has been released–”A thrill ride that keeps you on the edge of your seat,” or “A hilarious look at parenthood that also makes you think,” for instance. Then, as you write or rewrite, make sure you deserve those quotes.