Women are subtle in how they show interest. Well, by male standards, anyway. Even when women think they are blatantly obvious, they’re quite often being very subtle by male standards.
Learning to tell how girls show interest is a very valuable skill for a man, because it will allow him to operate with greater assurance he’s making the right move at the right time, and will also allow him to pick up the pace when a woman signals she is ready.
The last couple of girls I slept with surprised me a little at how quickly they were ready to get together. They gave me some hints that probably would’ve seemed fairly subtle; a friend of mine remarked that one of the girls I took home and bedded rather quickly quite recently hadn’t even seemed to be terribly interested in me, and that it just looked like we were having a good conversation. Being able to read the signals they gave me was the main reason I moved as quickly with them as I did.