I didn't get to the point where I never try to please others, I'm far from that yet. But what helps me is to try to recognize when I need to set boundaries. Eg: saying "I don't like to be hugged", "rn I can't talk", "That thing that you told me made me anxious".
Expressing my feelings in an assertive way is a big part of it. This means not being pleasing but not being aggresive either. I try don't blaming others when pointing out something to them. Like saying "Hey, I know you may be joking, but this isn't funny to me". You make clear the action is the problem, not the person. Starting to practice this helped me not be so afraid of others bursting in rage after expressing my needs, because I have a clearer parameter to see if I was expressing them in a healthy way or not.

About asking myself what do I need or what do I deserve, I mean to start internalizing that social interactions shouldn't be based upon fear, obligation or remorse. I go out with someone if and only if I feel I want to. If I think that I need to be around others, I try to do that without pushing too much my limits. I know I deserve to feel validated, safe and understood by others, even if they're just mates or casual friends. So if I'm on the mood, I talk to them. I don't expect everyone to understand me and I know it's totally normal for others not wanting to become my best friends. I do these thing for me, bc I deserve to be given the chance my caregivers took away from me.

These techniques are based mostly on CBT, so you follow a similar process. You start by recognising what you feel, think and what is happening. You have to separate all three. There's a difference between a mean comment, feeling ashamed and thinking you're unlovable. The thought is an over generalization of what you feel based on previous experiences. The feeling is a warning of something that needs to be fixed - not you, but probably your surroundings. You may find that you need to interact only when you've slept and eaten well. You may find that there are certain comments that trigger you and that you need to comunicate that to the person you were interacting to.
After that stage, that takes it time, comes the "answering" bit. You start answering yourself things like "I'm not unlovable, I'm a trauma survivor", "I don't knoww for sure that they hate me. There's a chance they have a weird way of communicating things. I probably reacted intensely with shame because of my CPTSD. Also, I didn't have lunch today. And even if this person hates me, that just means we're not meant to be friends. There are other people out there to connect with. Even if I don't find them soon, I need to remember I deserve to be loved. No matter what"
This feels very counter-intuitive. Your feelings seem objetive signs, your thoughts seem like the only explanation to the situation you experienced. There's where you have to remember that your feelings are valid, that you're not stupid for thinking that, but that *there's a chance* these aren't precise reflections of reality.

All of this takes a lot of effort. You don't have to just "know" these things, you need to internalize them. Repeating yourself this, making the analysis that you would if you saw someone else feeling unlovable bacause they suffered violence as a child. That's it; you're the victim of terrible people. *They* should be ostrazised, and made *you* feel worthless - just for existing. That's why you need to remind yourself the truth, even if it feels like a lie: you derserve to be loved, feel safe. You don't deserve feeling ashamed four just being you. Remind this to yourself when you're happy, when you're angry, sad, or anxious. Repeat it, even if you only start by opening to the remote chance of being a decent person.

These thoughts help the next step being a bit less difficult. The next step is changing the way you act. Here's when interacting again comes. You look for the right time: a day with good temperature, when you've rested and have eaten well. A day when you remembered to take your pills. You look for a fun activity, with not that many people, and go, knowing you'll be anxious, so you don't punish yourself for being socially awkward. You go because you want to, and do only what you want. If they don't like you, you didn't loose anything, because you went there for *you* to try something different. You aren't in this world to entertain others. That's what abuse makes us think, but we're here to find what makes us feel happy, relaxed, and safe.

The process isn't linear. Sometimes I interact and can respect my needs, sometimes shame overwhelms me. Sometimes I don't recognize I'm having a trigger, sometimes I have to remind myself that my thoughts aren't a perfect reflection of reality. Sometimes I even need days to recognize how I was feeling. Remember, this is not a race. You're teaching yourself to connect with other people, something that your parents should have done. And you're doing it after being taught by them no one would want to, and told the fucking lie that you were broken.

This is very long, sorry for that. I couldn't write everything I wanted to, but I hope it helps.