In my opinion there are two kinds of criticism; the good kind and the bad kind. Good criticism can point out flaws in your work in a constructive fashion and can ultimately improve your writing. Bad criticism points out flaws in your work but will be destructive rather than constructive.
The bad kind is easy to identify. If you are face to face with your critic then you will be able to tell a lot by their tone. If your critic is veering on rude, or even sneering then you can bet that person isn’t trying to be helpful. They either hate your writing so much they don’t even want to pretend to want to help you, or maybe they just hate you. Either way you are not going to learn a whole lot and that’s a pity because good criticism from an intelligent critic can help your writing a great deal.
If the criticism contains statements such as ‘I don’t like that main character,’ or ‘I don’t like stories about x,‘ then they are not helping you much because they are not telling you why.
WHAT MAKES GOOD CRITICISM?
If your critic tells you ‘I don’t like that main character because I find his continual sarcasm and kicking of cats as he evicts young families from their homes difficult to like,’ then there is something there for you to learn from.
Similarly, if a critic says ‘I don’t like stories about gangsters as a rule, but your gangster story was especially difficult to like for me as I love cats and your main characters habit of kicking them was repellent to me,’ then you have received vital information as to a key flaw in your work.
Writers are often friends with other writers and the best way to get decent criticism of your writing is from a group of your peers. However, if you are just beginning your writing journey then you may not know many other writers. In this case you may need to find yourself a writers group, or workshop. You can read some information about writers workshops here.
Sometimes criticism can be frustrating, particularly when we have worked hard on a piece and feel sure that it is good. It can be a real downer when it is not as well received as we had hoped. The best thing for you to do is decide is there is anything to be learned from it. If there isn’t then you can choose between seeking other opinions or ignoring them. I wouldn’t recommend going to the lengths this writer went to when annoyed by his writing class mates as you will see violence rarely solves your writing problems.