Jack, it's not the fact that you made the RP that makes it successful or not, it's about the quality of it. If it looks like someone spent a long time in it and had a really interesting plot idea, it's more likely people will join. To show you an example, I'll compare the introductions of the first RP I made to the most recent one I've made.
First one I ever made:
You are a clan cat. You come from one of four clans: Fireclan, Waterclan, Earthclan or Airclan. Times are teacherous, cats go missing jn the night despite the guards posted. Two cats form each clan must find this threat before all cat kind is gone. They must also find where they are. If you have read this far, put 'find' in other
Most recent one I've made:
To whom this may concern,
You have been one of the few chosen to join us at Jade Mountain Academy. This school offers higher education than most schools along with the chance to make friends with people from other tribes. Simply fill out the form provided, press the dragon insignia and you'll be good to go! We hope to see you soon!
~ Headmaster Mango of Jade Mountain Academy
In an alternate world, not quite Earth and not quite Pyrrhia, half humans half dragons live in tribes. These tribes have gotten into wars far too often in the past, so in order to help sort out their differences and stop wars, a few people banded together to create this academy.
See the difference? One seems much more developed than the other. One of them seems to be more original, and seems to have had more time and effort put into it.
A lot of it is also practice and perseverance. My first RP didn't get as much as a single reply from someone other than me. As I have joined other RPs and FWRPs over my time here, I've leaned how to create better RPs and better POVs. Just keep working on making RPs, and you'll get better. One great way to learn how to make a good RP is ask someone who has been here longer to help you make one. They can help you create a good introduction, a good plot, etc.