In your first ten pages, show us something we’ve never seen before. It doesn’t matter if it’s a tentacled star-beast or simply an original joke. Just give us something different.
One of the most recommended advices for aspiring screenwriters is “Write what you know”. Which makes sense because when you write what you know there is a chance that it will be authentic - and authenticity is a good thing (most of the time). But there is a problem with that advice and it’s that it might not be interesting at all and that’s at least as bad a being not authentic.
The better advice is obviously (which is pretty similar to people that invent products and services) to write the movie you want to see but doesn’t exist. Chances are that if you want to see that movie others want to see it as well. Pitfall of this advice is that the story might not be authentic or that you have to do lots and lots of research that can be a pain in the ass or even worse let the project become a never-ending story.
But there is a third advice that has worked for me pretty good so far and that is to combine these advices. That’s actually what successful writer-directors such as Martin Scorsese do: “Write the movie that you want to see by using what you know”. This increases chances that the movie will be interesting and authentic at the same time.
But don’t get hung up with what you know. There is probably still the need to do research and expand you experience and knowledge along the way. What you wanna see definitely trumps what you know.