Summarize this article in one sentence.
Even if you went through a similar experience, realize that everyone copes in different ways. You may describe how you felt during that experience or suggest ideas that might help, but understand that the other person may be going through a different struggle. Instead, try saying something like, "I can only imagine how hard this must be for you. I know how sad I was when my own dog died." Most importantly, never claim that your own problems are more serious (even if you feel that way). You are here to support the other person. Acknowledge that the other person's problems are real. Focus on listening to his/her problems and supporting him/her as s/he deals with them, not telling him/her that they're not worth the attention. Try not to accidentally minimize or invalidate your friend's experience. For example, if you try to comfort a friend who has lost her pet by saying, "I'm sorry you lost your dog. At least it could be worse - you could have lost a member of your family," you're actually invalidating her grief for her pet, even if you don't mean it that way. This could make her feel reluctant to share her feelings with you, or even feel ashamed of them herself. Another example of invalidation is the well-meaning, "Don't feel that way." For example, if your friend is struggling with body image issues after an illness and tells you that he feels unattractive, it would be unhelpful to reply: "Don't think like that! You're still attractive." This tells your friend that he is "wrong" or "bad" for having his feelings. You can validate the feelings without agreeing with the idea behind them. For example: "I hear you saying that you're feeling unattractive, and I'm so sorry that hurts you. That must really suck. If it helps, I think you're still very attractive." Similarly, don't say "at least it's not as bad as it could be." This can be interpreted both as a dismissal of the person's problems, and as a reminder of additional problems in the person's life. S/he may not be comforted by such statements, or s/he may even be offended by such statements. They can often feel impersonal or prepackaged. It is usually best to keep your focus on the person you are interacting with and what you can do for him/her. For example, you may be a deeply religious person who believes in an afterlife, but the other person does not. It may feel natural to you to say something like, "At least your loved one is in a better place now," but the other person may not get comfort from that. It's reasonable to suggest a course of action that you think might help someone, but don't stress the person out by bringing it up repeatedly. You might see it as an obvious, easy solution, but recognize that the other person might not agree. Once you have said your piece, let it go. You may be able to bring up the point again if new information comes up. For example, "I know you don't want to take pain medication, but I heard about a safer drug that might have fewer risks. Are you interested in the name so you can research it yourself?" If the person declines, drop it. You may think the other person's problems are petty, or less serious than your own. You may even be jealous of someone whose problems seem so minor. This is not the correct time to bring this up, and you may never have a good opportunity to do so. It's better to politely say goodbye and leave the room, rather than express your irritation. Some people think that "tough love" is an effective therapy technique, but this is the opposite of acting sympathetic. If someone is grieving or sad for a long period of time, s/he may be depressed. In this case, s/he should talk to a doctor or therapist; trying to get him/her to "toughen up" or "move on" is not helpful. This may seem obvious, but during stressful times, it can be easy to lose control of your emotions. If you find yourself arguing with the person, insulting him/her, or criticizing his/her behavior, leave the room and apologize once you've calmed down. Do not even jokingly insult someone who needs sympathy. S/he may be feeling vulnerable and easily hurt.

Summary:
Avoid claiming to know or understand what someone is going through. Avoid minimizing or invalidating the other person's feelings. Avoid expressing personal beliefs that the other person does not share. Stay away from pressuring someone to use your solution. Remain calm and kind. Don't act hard or uncaring. Don't insult the person.