Boundaries and safety is a deep subject and I will not be able to do it complete justice in a blog post. But I would like to offer some highlights.
Every human being has a boundary. Much of the suffering in this life is when our boundaries are violated and when we violate others' boundaries. This is done in a state of unawareness. Having the skills to keep your own boundary intact despite the assaults of other (unaware) people is the definition of safety.
In terms of communication, normally the issue would be psychological and emotional safety. Thus, it would be important to have some skills to not allow others' (unaware) barbs puncture our boundary; to learn and practice how to deflect, defend and defuse assaults on our boundary so that it has little or no effect on us. This is not easy to do but it comes with practice.
Similarly, I suggest that we absolutely do not permit ourselves the luxury (?) of placing others in a condition of violation and unsafeness due to our own modes of communication. It's not okay.
Start by affirming the sacredness of yourself and the sacredness of every human being on the planet. We are sacred by virtue of breathing. Yes, we are all at different stages of the journey, and some people have a lot to be accountable for. But it's hard to be human; it takes courage just to wake up every day. We all know that. We all know how easy it is to get lost, get off track, lose options, and then get stuck there. And we usually have no one else to blame but ourselves. So, for me, at least, it is better just to put the "lens of sacredness" over our eyes and hearts as the basic approach to life and to human interaction. Understanding other people as sacred doesn't mean you allow others to harm you if that is where they are at in life. But it does mean that you practice healthy protection of yourself and try to honor them at least in a basic way, and to not harm them.
Secondly, give up the "I have to be right and that automatically makes you wrong". You don't have to be right. And that doesn't make them automatically wrong. This approach may be out of your comfort zone to begin with but when you get used to it, it takes a huge burden off of your heart. You can be right for you, and they can be right for themselves. No human being wants to feel that they are wrong. This is against every fiber of the human nature. This makes sense, because it makes sense that we would already be trying to live, think and choose to the best of our ability or preference. That's just what being human is. So if your communication objective is to convince someone they are wrong, you will either fail, or you will have succeeded in assaulting their boundary and putting them in a state of humiliation (through a drama or through simply the force of your emotions and personality). It's also a good idea to learn some skills or scripts to use when others try the same tactics (unaware) on you. If someone seems invested in convincing you that you are wrong (and it would be outside of their boundary or business), then say something like, "I appreciate what you are sharing with me, and I'm going to consider that. However, please keep in mind that I've put a lot of thought into my position and I am happy with my choice."
Thirdly, learn some anger communication skills. Anger dramas are the most caustic and unsafe. Anger is an important and healthy emotion, or can be. But it is also powerful and takes skills. Anger is just one of those things you want to bring as much awareness to as possible; unaware anger can be dangerous. Even if fists aren't involved, anger can puncture the boundary and put us in a position of unsafeness. The odd thing is, is that anger usually arises because a person feels threatened and unsafe. That may or may not be accurate, but they or we are experiencing things that way. So find out healthy ways to express anger in communication and find out ways of protecting yourself from others' unhealthy anger expressions.
Fourthly, become conversant with all emotional vocabulary. Learn how to express, and talk about, whatever way you are feeling, without assigning fault. Also allow other people to express their feelings and maybe you can even be strong enough to handle the situation when they don't know how to do it. But if you can see what is behind their drama, and refer to the basic emotion from them, you can defuse the drama and arrive at communication. Your friend comes in saying, "My boss is such a fraud! I can't believe she [fill in the blank]! I don't know why I keep this job." Instead of addressing what she is saying out loud (she is assigning blame and is unaware of her responsibility and is inviting you to take a role of helping to bash another human being)--you can address the emotion that she didn't say. "You sound frustrated."
So examine your own communication. See if there are any ways you are communicating that, if you had to be on the receiving end, you would feel unsafe. So don't do that to other people, either.
Also see if there are any communication or interaction situations that you are regularly subjected to, to see if you are feeling unsafe or your sense of peace (boundary) violated. If yes, then seek to learn some communication response skills that can restore your boundary, your safety and your peace. You deserve it.