"Establish a policy of taking all criticism as friendly. Once you insist to yourself that the other person is well intentioned, you'll get value from legitimate criticism, if there's any there to get, and you won't be bothered by the rest. When you concede a critic's good will, you disarm an attacker and encourage an ally." - Carroll O'Connor
Most people become defensive when they are criticized because it feels like you are being personally attacked. That is especially true if you put your heart and tremendous effort into something you have done. You feel that you have invested a part of yourself in it, and any criticism is not just directed at that particular project or effort but is directed at you personally.
However, being defensive prevents you from benefiting from criticism. Trying to explain why what you chose to do was right keeps you from considering how your choice could have been better.
Carroll O'Connor's advice removes the perception that you are under attack. Assuming the person is trying to help, not hurt, does not trigger your defenses.
Then you can unemotionally consider the validity of the feed back you receive. If you decide that the criticism is valid you can consider ways to put it into action. If you decide that the criticism is well intentioned but misguided, you can forget it.
One of the ways in which I receive criticism is evaluation forms filled out when I lecture. Some educational programs compile the comments from each class and forward them to the presenter. Because they are just a list of comments I do not know who made them. So I assume that if somebody took the time to fill the form out they were trying to be helpful.
Although I try to be very organized for my lectures, I received one comment earlier this year that a lecture I gave was unorganized. I decided that was not a valid comment because that class had unusual circumstances. The instructor before me ran over so I had less than two minutes to get set up before my class began. Also, there was no table in the front of the room. I had to put all the visual aids that I planned to use on one chair and then put them on another chair when I finished with them. That made it difficult to immediately find what I wanted to use. (Since then I have tried to make sure that a table is available for my use.) Later in the year I received another comment about not being organized enough for a class. That means I need to try to figure out what caused that perception. The majority of my feedback is that my classes are extremely organized, but I am always trying to improve.
Sometimes a comment seems like it isn't valid, but upon further reflection it turns out to be very useful. Assuming that the person meant to help you means you can reconsider what they said. I received a comment that where I stood during a lecture blocked the screen so people couldn't see my PowerPoint slides. My first reaction was that since there were plenty of empty seats the participants should have sat where they could see the screen. However, I discussed the comment with Lee Mullally, who is an expert on education. He said that speakers are usually trained to stand downstage because it is easier to connect with people if you are closer to them. Lee said that principle isn't always valid when using PowerPoint. If the PowerPoint screen isn't higher than your head you should stand beside it so you don't block anyone's view of it. So, not being defensive allowed me to eventually benefit from the comment.
If somebody knows they can make a critical comment without you getting defensive, they are more likely to make additional comments that may be helpful. (I am better at this in my professional life, than my personal one.) If somebody is trying to upset you, but they don't get the result they desire, they don't have any reason to continue.
How can you develop an attitude that criticism is friendly? How can you evaluate criticism to determine what is valid and what is misguided?