Women in writing. Fun. As a guy, to write about the opposite sex is an absolute minefield. I once had a character whose role was simply "the girl" and was only created because I thought I had to have a love interest in my story. It took plenty of tightrope conversations with real women on how genders differ before I could make female characters that I was satisfied with and came across as more natural. Surprisingly, I learned that for most of the great characters in fiction, gender doesn't really matter. Having a specific gender doesn't make a great character, but having a great character deal with gender-specific traits does make for great story-telling.
How do Men and Women Differ?
To answer this question I had to sit through and study many "girl talks" or what I like to call "Gender Banter," because guys have "guy talks" too. From field study and conversation, I learned two objective things on how men and women differ. They are first the obvious biological traits, as well as the societal roles that are attributed to each gender.
Biological Traits
Biological traits are the traits that are ubiquitous across cultures. They're the way men and women differ on the most basic biological level. In writing, there's of course the reproductive organs as a default, but there's more to it than that. Women tend to be more dextrous than men and have a higher pain tolerance, while men tend to be larger in physique and have more muscle mass.
Now it seems at first as though that's not much to go off of, but there's a glaringly obvious story-telling device that can be explored more thoroughly thanks to women's genetic traits: motherhood. It differs vastly from the fatherhood role in the way motherhood experiences child-bearing and fertility stages in life firsthand. A good example of using this in a story would be a mother trying to corral her children across a poverty stricken land or in the middle of a war. That could be a powerful story, and that is a biological trait. How do biological traits differ from societal traits given to genders?
Societal Pressures and Gender roles
Societal pressures are where plenty of writers, including myself, have made mistakes. This is most common among male writers when we assume that things that are related to being female are therefore inherent to being female. Things like "girls like pink" or "girls love make-up" are what we write into our stories as what all women are like. When men make that assumption, that hurts the female character as if that aspect cannot be changed, and change is where the character is found. Instead, male writers like myself need to understand that those are societal pressures, and not always realities. Society encourages girls to like pink, or encourages them to be wear makeup, but how the character reacts to that pressure can tell the audience a lot about them. Also, the pressures society exerts on females can vary. One could just as easily have a society of "girls wear black" or " girls swing first" because these pressures are malleable in story-telling. Of course, if the character rejects all of society's pressures, ironically, writer's will get just as stereotypical and uninteresting a character as if they conformed to all those pressures. There are reasons behind why women or just people follow certain pressures, and why they reject them. Also, those feelings on those pressures can change as the character's circumstances change. Once male writers understand that, they can craft many fine female archetypes.