Part of performing any artisan craft for the public is receiving less than flattering feedback to downright hateful rants. As a hairstylist, it's something I deal with daily on a professional basis. What I've learned over the past 15 ish years in the salon industry, and 20+ years in the art community, is some people will never be pleased or satisfied. Also, opinions are like a-holes, everyone has one and it's, more often than not, full of crap.

At the end of the day, it's about whether or not YOU are proud of your work, especially with writing. Take any constructive criticism into consideration, and dismiss the rest. And remember, fanfic is a hobby. It's something you're doing ultimately for your own enjoyment and growth as a writer.

As for methods to developing a thicker skin, there really isn't any. Mostly it's figuring out what works for you, and constantly reminding yourself to take a step back, breathe, and move along.

I can tell you how I handle it but, it rarely works for others. I simply take the comment for what it often is, a caustic comment from someone who read the work and saw it as better then their own. There are a lot of other reasons but that one is easier to apply to most toxic people who reply.

If that doesn't work, then the easiest way is to simply read them and take from them the criticism that has value and ignore the rest. Don't let the toxic people get to you, keep on writing and keep on improving and soon those people will just be a footnote.

I've been writing and posting since I was about 13/14 and I'm now 21 but I'm still not really able to deal with hate well. Nothing on here, thank god. Not even for this fandom in particular, but for my Ranma fics. About half or a third of my anonymous reviews are negative.

I'm no fantastic artist, and I understand the difference between criticism and hate. A lot of the criticism I received in the past was borderline hate, and it discouraged me a lot because I was still in middle school, moving to highschool, but I tried using it as a way to get better and tried taking some of the complaints to heart. I began triple checking my works and using a grammar program alongside my writing program.

And personally, I think I've come to a long way and there are people who do generally like what I produce! I get that you can't please everybody, that not everyone will like or enjoy my work, I get it, I just want to know if there's a way to not take it so personally? Like, not let it get me so discouraged?? And honestly I'd like to turn off anonymous reviews on ffn if possible, but I only found I could moderate them :T

Just any tips on how to better handle and improve from this?

on a more positive note, the grammar program I use is called grammarly, and it's free to use, just need an account, and you can write directly there or upload content to correct.

KoD is right... filter the childish adjectives and learn from it... or if nothing else, thank them from taking time out of their obviously busy day to comment on your work in an attempt to help you grow as an artist. ;P Usually commenting like that once or twice is enough to get the trolls shaking their heads.
My son used to say something similar to some local bullies. (would drive them nuts)

I just say whatever to myself and keep on rolling, flames and harsh critics bothered me so much more when I was younger and took it too personally. But now I'm just like if I'm satisfied with my writing then I'm happy. But there seems to be and have always been a lot of great and positive peeps on this wonderful site.