I'm surprised no one else has mentioned the other half of sitting like a lady...posture. Most of the time women don't lean back all the way in the chair and settle in like guys do. They tend to sit with their butt against the back of the chair and keep their back straight up...often not touching the back of the chair at all. It's not 100% of the time, but pretty close. I noticed this a couple years ago, and since then I've noticed that most do sit this way.
Someone mentioned legs crossed while eating, and I've noticed a lot of women do that in restaurants. I've tried, but it's hard to cross my legs under the table.