Think before you speak and take five big breaths before you react. Use the five-second rule.
My five-second rule is when you are in communication with someone, give yourself five seconds before you reply. This is most important during intense conversations. When you are upset with someone- when the communication really needs to get through, take five deep breaths before you respond to what the other person has said or done.
They don't even need to know it and they won't know it. You can do this in a very subtle way. The deep breathing brings oxygen to your brain which allows you to think clearly and it also buys you a brief amount of time in which you can think of what you want to say. This can guarantee that who you want to be in this conversation and what you want to say come across clearly. We often get into trouble when we have a knee jerk response to what someone does or says.
This is a good life coaching and CBT tool and it works. Try it and enjoy the benefits.