After the first date, if not on the first date itself. You basically assume she's your girlfriend and treat her like your girlfriend. Yes, with the touching (Kino) and everything. (Maybe not kissing so early on though) If she's not interested, she'll let you know just then, and you can next her. Which saves you the trouble of trying for a long time, going through one-itis, and maybe falling into the friendzone in hopes of her getting attracted to you. What you do instead, is from the first date itself, treat her like your girlfriend. As the dates go by, from first date to second date to third to fourth and so on, gradually increase the touching, until it leads to a kiss. You'll know when it's time for the kiss. You'll feel it. When you do, just remember to
do it, and not over
think it, or you'll pass up the perfect chance. Always think with your other head, if you know what I mean.

Good luck, champ!