Try explaining the setting and what fascinates you about it.  That's how i got a few takers for my Deadlands RP.

You could explain concepts you want to explore too.  Like if it's a Grim Dark Dinosaur RP, or a goofier one, or you could relate it's tone and themes to another game or series.

Witcher with Dinosaurs VS Warhammer with Dinosaurs VS Monster Hunter with Dinosaurs