A friend and I ran a web comic together. He drew it. I wrote it, marketed it, did the site management, and handled the posting. SO I got all the anxiety about posting. (Yippee.) But it was important because I learned some things. He never felt the anxiety because he wasn't responsible for posting. He was removed from the process, so to speak. So after we stopped making our comic and I started my own, I carried over a few things.
1) Do as much as you can ahead of time. I write my scripts way ahead of time, and I review them every time I go to add more. So I can improve the dialogue, panel descriptions, etc. The more I have done the more comfortable I am with the results.
2) BUT the actual comic/art is hard to do ahead of time. So do the things that build skills whenever possible. You know the stuff, thumbnails, life drawing, and sketching. Confident in skills helps be confident in the process.
3) Automate whatever you can. I don't just mean posting pages. I automate my social media too. It keeps my presence out there, and I don't have to worry about it. The more I keep off my plate, the more I can focus on creating the best work I can. It also means you're not actively pressing that dreaded publish button right before you receive a response.
4) Accept your skills for what they are. I am not perfect. I am no expert. My comic isn't the best thing in the world, and it never will be. However, that doesn't mean I have to let that add to my anxiety. Deadlines work wonders for acceptance. If you make yourself stick to a deadline, you have to accept your flaws at some point. Nothing is ever "DONE" it's always in process.
Don't get me wrong, I still get nervous every time I post. Every damn time. But I think my little tips help me. Hell, I get nervous responding on the forum. I'm no expert and who knows if what I say counts for anything, but this seemed like worthy thread to chime in on. Everyone deserves to know they're not alone in artistic struggles.