I’ve never made a woman orgasm, I do not understand what I’m doing wrong. Help!

I do not believe I have ever made a woman orgasm. I’m 37 years old and I’m a virgin in a lot of things. I have never used my mouth on a woman, I don’t do anal, I’ve never played with a womans ass, etc. I’m super nervous about trying new things. I just want to know what I’m doing wrong. I just wanna make a woman happy. Idk what’s going on. I’ve been told my dick size is an issue (5.5 inches) and the truth is it hurts me. I’ve been with over 300 women and I’ve always been careful. I’ve always made sure to use protection and to keep things clean, etc. I’ve been tested for stds and I’m good! I want to know what I’m doing wrong. I’ve tried to make women cum with vibrators, stimulators, different condoms, different positions, I’ve had women cum in my mouth while giving head but I don’t think it counts as I didn’t make it happen, I’ve never made a woman squirtd, I’ve tried to play with women’s butts etc. I just want to know what im doing wrong. I do not want to make 301 women unhappy! So here is my question. What is the best way to make a woman happy in bed?