I notice if she seems glad to see me. It could be in eye contact as many have expressed, but mostly if she leans in for or accepts my approach for a greeting kiss. I'm not talking about tongue wrestling right off the bat, but a soft kiss and embrace usually tells me what to expect.
And, if I've seen her before, a sloppy kiss followed by her turning around, showing her ass ( as per London ) and hopefully with an up-skirt and no panties. That way if I want to take her up against the door right off, I can, LOL
I once visited a lady who was in town offering incall. She met me at the door wearing a loose T-shirt and pajama bottoms. Even though she was attractive and the date went well, I couldn't help but wonder just how important I was to her that she was so insensitive to my desires about her appearance.
If she comes to me I expect a dress and maybe thigh highs and no panties. If I go to her I expect lingerie of some sort. So yeah, I guess the way she dresses is important as well