[quote=@Proxi]Well, unless you overexaggerated her femininity or basically just made her a man with a vagina.[/quote]

Where would the middle-ground be? Not being difficult, I'm legitimately asking, because I think that is probably going to be the answer to OP's question. 

I always felt it would be awkward to focus too much on referencing physical differences ("She felt the weight of her breasts as she jogged") for the same reason it would be awkward to overuse male differences ("The jungle was so humid his testicles stuck to his legs"). Actually, this reminds me that there is a women who writes historical fiction short stories from the perspective of a gay military officer in the 18th century (I forget her name or the name of the stories), and when reading one of those I was pulled out of the story when she used a line sorta like "As he climbed on the horse for battle, the fear made his scrotum pull tight". It was weird because, though I've been scared of shit plenty of times in my life, I don't think i've every consciously thought about what my scrotum was doing while I was afraid. I feel like it was one of those things she wrote because, as a woman, the idea seems like it would be pretty noticeable and worthy of mentioning, but for men it's sort of a tertiary thing. Likewise I always figured over-focusing on female physical traits can end up distracting. 

And I also think too that the line for femininity is kind of complex. There is a line that I figure we all kind of know, but it's difficult for me to try and put into words, so it is difficult to know when I've breached it. I've also, like the OP, been told before that my female characters didn't seem very female (by a woman as it turns out), but she couldn't tell me why, and I can't exactly pin point it either. 

For OP, I agree with everyone that a sample would help.