A very basic closet item for a classic woman is a white shirt. They are very versatile and you can wear them all year round. My personal collection has been growing since I started working, although finding my size is still a problem. So much so that I had one made from scratch when I was able. Even so, the one that I like the most and I looks best on me is one I bought on my sabbatical trip last year. It’s the only one I own that looks as if it’s mine. Español aquí.
A few years ago I read How to be Parisian Wherever You Are, by Anne Berest, Audrey Diwan, Caroline de Maigret, and Sophie Mas; and all I can remember is that a Parisian woman wears a black bra under her white blouse. Because I am a good learner, I do the same. I also recommend having your shirt well ironed and stiff so that it looks well structured when wearing it. I love wearing it with either with jeans for a casual Friday or with tailored pants for office days.