I like them untucked over pants or a pencil skirt for work if they are nipped in at the waist a bit. And I usually wear them with a more feminine shoe with a bit of a heel. If I wore the straight version, untucked, over pants with a flat, androgynous oxford or loafer, I would feel a bit sloppy. If it matters, these shirts often have a bit of lycra in them, so I can wear them as truly fitted for my body without being uncomfortable in them.
The other way I like to wear them is open, like a jacket, over a fitted tee, tank, or camisole. The layer underneath has to hug my body and have a v or lower cut scoop neck for this to work. And even though a straight cut is acceptable in this case, it can't be oversized or baggy if I want to look pulled together. This reads as a more casual look to me than what I described in the first paragraph.
Which doesn't mean I don't wear oversized, baggy ones with my jeans or leggings. I just don't pretend that I look sharp in them. This look is usually reserved for hanging around the house. Even in those cases, I tend to go for shirts with great colors or prints. I used to manage a menswear store, and many cool paisley and floral print mens shirts managed to follow me home during that time. I may revisit my old menswear shirt + leggings + cool boots formula again this fall. But this time, I'm going to see how it looks and feels when I belt in the shirt.
