I speak up for me better now. When I am upset, I now more often (if I believe the relationship is worth it) will tell the person, or ask that they do not treat me a particular way or change the way they speak to me.
This has been the singularly most important change.
I am not where I should be in terms of standing up for myself, but I am not where I used to be, and I will continue to move.
A friend shared a video with me earlier today. I intend to listen to this again and again, and paste extracts from this speech on my wall at home, so I can be continually reminded. I expect this to significantly change the way I see me, and essentially how I allow myself to be treated by others.