It's hard receiving criticism. Especially when you're a writer or artist or some sort. You just tend to be more susceptible to it. But honestly, if you plan to write and get your work published, you better have some thick skin, because more likely than not, you'll be rejected.
But being rejected by a publisher, is one thing, being abused by comments on a blog, or by flame reviews on a site like fanfiction.net or youtube is quite another.
When someone critiques your work, it's important to understand that they are telling you how they feel about it. And you have to understand, that the feeling is valid. They didn't like it. There are a few ways to know if someone likes your work or not while you're online. I measure the fact that I have consistent readers, every week. I have some who choose to follow me. So if/when I get a bad review, I know that it's just how they feel, and know that it's not how everyone feels, because I do have some people who like my work.
But, even if no one was coming to this blog, and no one read my work on fanfiction.net, I'd still be doing what I'm doing. Because this is practice for me. A way to expand my writing.
But, there's something else you can do with negative reviews, you can use them to write or draw or paint better. Use it to motivate you to focus and try harder.