This sounds simple enough but you might not realize how much you don't do this. I know I am just starting to find out.
Most of the feelings we have are 'caused by', or are reactions to, things outside of us. External causes. These external causes seem to have power over us. Anything that happens in the world seems to be 'reality', and what is real is true. So as anything happens, it's as though it is a statement of what is true. For example, if someone attacks you, and if it's a statement of what is true, then its saying "it's true that you deserve to be attacked".
Left unchecked, your ego will take this suggestion and agree with it. "Yes, it's true that I deserve to be attacked", Ie that you don't deserve love. And in order for you to align with that, you'll attempt to CHANGE YOURSELF into a different identity. You'll try to make yourself into "a self that isn't loveable". And what will that feel like? It'll feel like guilt, like unworthiness, like sadness, like shame.
So 'reactions' are actually your attempt to comply with the power that an external cause is trying to have over you, which is trying to dictate and change what you are. So if you go along with it, you will 're-act' by acting as if you are what it tells you you are. In other words, you attempt to be an EFFECT of this external cause. By being the effect, you are 'affected by' it. And this doesn't feel good to turn yourself into a condition that runs against your true nature.
You'll also notice that when you have these reactions, these effects, which accounts for most emotional responses other than real love or joy, the way you EXPERIENCE the feeling entails a sense that the feeling isn't just inside your body. Or that it isn't yours. Because you perceive the feeling as having been caused by something external, the feeling ITSELF will feel like it is connected to, attached to, and dependent upon that external cause. If that thing caused you to feel this way, then the feeling essentially "came from" that thing, and was dictated to you by that thing. In your awareness, as you have this reactive feeling, you feel like your feeling is going outside your body and projecting onto that external source, or at least that it is "about" something other than you.
You're very used to this, so it seems to you that it's completely normal for reactive 'feelings' to feel like they go outside your body. Since you're so used to believing that you are "affected by" external stuff, and that this upsets you (changes you into an upset person by redefining what's true about you), you don't believe you are responsible for your feelings. It's someone else's fault. Something else is making you upset. It's not 'yours'. So quite literally you perceive that YOUR OWN FEELINGS are NOT YOUR OWN FEELINGS, that they belong to someone or something else "out there". And that therefore you don't have control over them. And this makes you into a victim. This also has a lot to do with why you block and deny and do not want to feel these feelings, because you believe they are not really yours.
Now, what I'm going to suggest is that you need to learn to take full responsibility for the *experience* of feeling. Whatever the feeling is, no matter who seemed to create it or cause it, you need to OWN IT and own up to the fact that this is YOUR FEELING, not someone else's. And that means, this feeling is actually INSIDE YOUR BODY and not extending out to project into other people as the cause of it. And it also means, these feelings are not really there BECAUSE OF someone or something else, but BECAUSE OF YOU.
A phrase which I've begun to remind myself with is:
"I am responsible for these feelings".
So no matter what's going on, if I'm feeling upset that my neighbors are making a lot of noise.. I have to say, "I am responsible for these feelings". I'm not having these upset feelings 'because of' my neighbors. I'm having these upset feelings because I AM THE ONE who is having them, which means I am the cause of them, which means they come from ME. They're mine. If I were to assert that I'm being caused to be upset by my noisy neighbors, then I would have to believe my feelings are caused by them, so my neighbors are responsible for my feelings, and not me.
Or how about, your parent doesn't love you enough and you come to believe it means you're unworthy (because you believe they're treating you with the truth so that must imply you don't deserve love). If you feel hurt because of them, by them, or they caused it, then you will not be responsible. So long as you disown how you feel, and blame the cause of the feeling on them, you are stuck. So really... your feeling of hurt or abandonment or unlove or unworthiness is NOT because of them. It's NOT them that caused it, otherwise that would mean these are their feelings. Yes, you tried to take on their feelings as your own. But it's not yours. What YOU are feeling is YOUR feelings and YOU are the one choosing to feel this way.
"I am responsible for these feelings". This frees you. It affirms that no matter what you feel, that feeling is IN YOU, because it is YOURS. It's confined to your body. And as you claim this responsibility and detach from blaming it on someone outside of you, you'll notice something odd happens.
You'll start to become aware that no matter what, no matter how severe circumstances are, no matter who is doing what 'to you', your feelings are YOUR responsibility. Which means you cannot project the onto anyone else or blame anyone else. This is a whole new level of responsibility. To walk around in this world with all kinds of stuff happening and people doing stuff and to NOT see them as having the POWER to CAUSE YOU to feel a certain way. This is a step toward invulnerability.
This takes pracice, mainly because we're so used to being victims and so used to tying our feelings to other people and events. I have to own up to the fact that no matter what I'm feeling or 'why', I am ONLY feeling it because I WANT TO and because I'M CHOOSING TO. Otherwise I am a victim. These are MY feelings, and it's nobody else's fault.
The odd thing that happens, and I've found this quite unexpected, is IF and when I claim responsibility for what I'm feeling, quite often I suddenly start laughing, or the feeling disappears really quickly. If I see that this feeling is entirely within me and has nothing to do with anyone else, it has nowhere to go. This perceptive change of 'being responsible' prevents me from buying into victimhood, or into believing that someone external 'caused this'. This SETS ME FREE. It completely undoes the foundation of victimhood, which largely undoes the foundation of the feeling itself, which really was just a mistaken thought or attitude.
I've also noticed something else very weird. A couple of times now I have been in situations where, normally, I would have a 're-action'. Like getting cut off by a driver in traffic. I noticed I was 'supposed to' or normally would react in some kind of anger or skapegoating. But instead, I didn't do anything. I stayed responsible, which meant staying responsible for my own feelings, which meant that person didn't have the power to cause me to feel differently. And I watched as my feelings.. ... didn't change. It was like, I'd switched off 'reacting'. Same event still happening, but no reaction. Hmm.
There is something else odd that I've been experiencing. If all my feelings are my own and I am feeling them BY CHOICE and not really because of or at the effect of anyone else, then I must be quite literally walking around INVENTING feelings on-demand, just spontaneously, in order to take the opportunity to try to scapegoat, but nevertheless creating these feelings for NO REAL REASON. All of my supposed re-actions are really just me choosing to feel something at a given time, all on my own, all within myself. It's got nothing to do with anyone else. Ano if that's the case, then WHY am I doing that? What's the point? Maybe I should just stop making this shit up!!
This is part of how we show our brother that they have not done anything to us, by demonstrating that WE have not been affected. We haven't been affected because we are not the EFFECT, we are the CAUSE of what we feel. This happened to me one other time too and I found it remarkable that, even in a situation which would have 'called for' a big reaction, there was no reaction at all. It's like being unplugged from the story. Being immune and invulnerable. It seems like CHEATING! Lol .... But it works.
I know I will keep practicing this and will continue to become more responsible for what I am and what I feel. I encourage you to do the same.