My experience is that about half will play hard to get. The other half will drop hints, sometimes very obvious ones, and wait for the man to take the bait.
A very few times, I had women come on to me directly. This was the exception to the rule. I think in most cases they were inebriated or looking to dish out relationship revenge to someone else.
One very sure sign that a woman is into you is if she offers to pay for something, like food, drink or entertainment, without being prompted. This is rare and falls into the indirect category. I have never found it to be wrong, however.
Another sure sign is when a lovely women sits on your lap within a few minutes of meeting you. That happened to me 46 years ago in Northern Germany. It was a summer for the ages, a TDY at a German firing range on the Baltic Sea.
The nearby town came to life during the summer, thousands of factory workers took vacation about the same time. Greatest concentration of newly divorced women I've ever seen. They fell in love with my soldiers who gladly reciprocated. We were the only Americans for 200 miles.
We carried on our relationship for my last two years in Germany. Nothing but fond memories of our time together.