The examples in How does a woman show her interest in You show that a woman is specifically interested in you. But how do women "tell" that they are ready to be approached because of a general dating mood?
Women will wear shorter skirts
Women will wear clothes that let her body "shine thru"
Women will cut out bras.
Women will use more perfume
Women will use more make-up than usual
Women will wear a redder lipstick
Women will sit with uncrossed legs or They will change the crossing often (left leg on top, right leg on top)
Warning: It may very well mean, that such women have their ovulation taking place and thus can get pregnant.