We live in an age where children often get praise for participating not succeeding, when they grow up they don't understand that accomplishment is required for real success. There is an illustration I have had to use for myself since at one time I was rather thin-skinned: Work makes your skin tougher and some blisters and pain go with that work. If a writer can't handle a few blisters from a constructive fellow writer than he is not well suited to being a professional writer. The good news is we can change, by working, now I welcome real critics. If you are on the receiving end of a critique, then say “Thank you” don’t add any justifications or explanations, if such are needed then you didn’t do a good job explaining in the original work.
There is a technique for giving criticism that is easier to digest and I have heard it called the Oreo Approach. It goes as follows. Say something positive, give the hard criticism, say something else positive. The first positive builds them up, the critical knocks them down a notch then the final praise leaves them to feel good about what you said and themselves.
If there aren’t two positives, don’t critique it. Anything lacking even two good things to say about it is a waste of time and the person will never appreciate what you say. Be very careful about offering unsolicited advice since people seldom wish to get it, regardless how much they need it.