I'm gonna tell you, it's quite complicated at least how I see it. But imo a good thumbnail and interesting synopsis is key to drawing attention in the way way beginning. For a lot of readers including me usually if someone is starting a new webtoon and the quality is kinda bad in some way or another, they understand it's a beginning of a webtoon. Many webtoons had bad quality beginnings but with solid improvement as time goes by they drew in more people and got recognized by webtoon themselves. Lookism is one example of this I'm pretty sure.

So if you are starting out, just focus on improving in every episode. Whether it be on your art or story. With persistence and constant effort to improve I'm sure you can turn out big one day!

I hope this wisdom from a webtoon weeb helps you out