I don't think there's any great mystery to writing female characters, so long as you talk to them. If you lived in a monastery and never met any women, maybe it would be difficult.
I like to create imaginary characters and events around a real historical situation. I want readers to feel: OK, this probably didn't happen, but it might have.
I use a professional researcher in New York who does all the legwork, all that stuff which would take me days and weeks of calling, waiting for people to call back.
In my books, women often solve the problem. Even if the woman is not the hero, she's a strong character. She does change the plot. She'll often rescue the male character from some situation.
James Bond is quite serious about his drinks and clothing and cigarettes and food and all that sort of thing. There is nothing wry or amused about James Bond.
The research is the easiest. The outline is the most fun. The first draft is the hardest, because every word of the outline has to be fleshed out. The rewrite is very satisfying.
There was a very serious communist strain among American intellectuals before the war. America was a more tolerant place in those days, and Communists were not treated as pariahs. That ended with the McCarthy era.