One special sort of IOI is the invitation. This is when a woman you haven’t met yet gives you a signal showing that she wants you to approach her. Identifying these takes a certain amount of social intelligence that you only get with experience. Most men completely miss invitations, while others go to the opposite extreme and think every glance indicates sexual passion.
How should you respond to an invitation? Some guys advise that you respond immediately to such IOI’s, citing the three second rule. This is usually the best course of action in busy, social environments. When you’re in a location where people go for some reason other than socializing – at a coffee shop, for instance – you might want to wait a while after her invitation before approaching. Running right over to her comes off as reactive, since you’re effectively jumping at her command. As always, doing something (assuming you’re interested) is infinitely better than doing nothing out of fear. “Hi” is good enough, as long as you come across as confident and secure in yourself.
In general, girls who issue an invitation in a daytime environment are more interested in you than girls who do so at night, probably because not many girls go out during the day with the explicit intention of talking to a lot of men. These girls are more likely to make an effort at conversation, so you should stick to whatever kind of game/conversation you’re most comfortable with. You’re going for a layup here: it’s no time to try your new trickshot. She liked you enough to invite you, so as long as you come across as an interesting and confident guy she’s likely to stay attracted enough to see you again. At night, girls are more likely to issue invitations to men just for fun, so you shouldn’t assume she already likes you.