My girlfriend (22F) wants me (23m) to use words of affirmation in the relationship. I don’t know why I find it so dificult, any tips?

She told me that she wants me to improve this a few weeks ago and I have been so delusional and not worked on it at all. She commmented on it last night how I haven’t improved this and it really affected me. I really want to make this work but I really struggle with it. I feel it isn’t natural for me but I want to change that. Any tips?