I've been at this a loooong time. It's about putting up boundaries instead of people-pleasing. About accepting yourself as you are. I suggest practicing saying things like "I'm unable to do this." "I'll have to pass on it." Don't get into a lengthy reason why or try to explain yourself. No is a complete sentence. And when someone is going on and on about his/her problem, make an excuse and leave. "I have to go" and then walk away.