Well, I've been writing online for a while and my trick is pretty much to remind myself I'm not getting paid enough to stress myself out, lol. I think it's important to remember that no one expects perfection from you, or any other creator. What readers expect is just a good story, but good is subjective, so the best you can do is create the story you want to tell. Not everyone will like it, like with any other story, but as long as you enjoy the story you came up with and the process of creating it, that's what matters.
Back when my work was getting a little more popular on another site, I started to feel some pressure about what my next book would be and whether people would enjoy it. Then I realized it didn't matter. There's a lot of books I've enjoyed, but just because I liked them doesn't mean I liked the author's other works, and that's okay. I still think they're good! So even if the things I create aren't for everyone, they're for someone out there and they're for me.
Ultimately, it really comes down to learning to write for yourself first and letting go of self-imposed expectations that give you anxiety. Have fun with the process and be kind to yourself!