The biggest thing that looks amateur to me is to have a modern, or mostly modern woman historical fiction. Yes, it happens with men too, but in a lot of the unpublished fantasy/historical fiction I see a self-confident woman who doesn't need a man and sling a sword/run a business as well as any man and doesn't seem to suffer any sort of sexism as a result.
Modern social mores is a common one, I agree. It is too easy for a modern writer and a modern reader to react as a modern person would and impose those morals on the characters. It's not just sexism, but racism and classism too.
On the one hand you have to accept that sometimes the MCs are exceptional people who are more enlightened than the average person of the period. Often the story is about how the bigoted old baron came to understand that the woman who cleaned his toilet is an intelligent and thoughtful woman he might fall in love with or how the staunch Nazi forms a friendship with the Rabbi and learns that the propaganda is not true. I think it becomes annoying when everyone in the world is happily egalitarian - as if someone from the modern day had travelled back in time and taught them all 'the error of their ways'.
I did put a throwaway line in Gods of the Sea when introducing Rachel - who is a strong woman of the type you describe above. It was a comment about how the country she came from is considered 'weird' by every other place because of their strange attitude to women (they could own businesses! Dress how they like! There was even women in the Government!) which I think covered that issue nicely.
There was a LRP game I played where the players displayed this sort of behaviour. It was supposed to be authentic medieval (around 10th - 11th century) attitudes and as a result any female players got bonuses to make up for the fact that they would get sexism. Trouble was many of the male characters were too nice and modern to actually play that out so they got the bonuses for nothing anyway
It is very difficult to play or write or think like a person from a historic period...

