The best way to keep an argument calm is to be as kind as possible. Respectfully acknowledge the other person's viewpoint, even if you don't agree with it.

Quoting incorrect information weakens your point, which is essentially an automatic loss. 

If the other person is truly getting out of control, it's often best to disengage. A perfect phrase to drop is: 'If you say so.'

During an argument, think like a salesperson and try to be as persuasive as possible. Facts don't persuade, emotions do.

Words like "everybody, always, never" are broad generalizations.

Step into the mind of the person you are arguing with and see their view.

Instead of casting blame and saying things like "you did this" and "you did that," try using "I" statements.

Losing your temper will only anger the other person, which will heighten the argument.

Go back to the concept of talking with someone rather than talking to someone.