It's easier to agree than disagree．The following tips(建议)can help keep disagreements constructive(建设性的)．
Don't make it personal．
If you get upset, it can help to remember that you're mad at the person's idea, not the person．
Never criticize the other person's idea．
Instead of saying “That's a stupid idea!”, try：“I don't agree, and here's why．” Never shout loudly and you'll have a much better chance of getting your idea across．
Use “I” statements to communicate how you feel and what you think．
Using “you” statements can sound argumentative(好争论的)．For example, telling your mom “You always remind me about my chores when I have a lot of homework” has a very different tone(语气)from “I'm under pressure because I have a lot of homework tonight．Can I do those chores tomorrow?”
Listen to the other point of view．
When the other person is talking, try to stop thinking about why you disagree or what you'll say next．Instead, focus on what's being said．When it's your turn to talk, repeat any key points the other person made to show you have paid attention to what was said．Then calmly express why you disagree．
Stay calm．
This is the most important thing you can do to keep a conversation go on well．