There is no three-day rule or anything else that governs when you should call a girl. Presumably, you’ve been talking for a while before you got her number, so there may not be a lot more to say an hour later. But sooner is usually better than later.
A few tips:
• Before you say goodnight, make an excuse to call her the same night or the next day. Maybe you will check the date of your friend’s party, find out the name of the club where Gangsta Land is playing on Saturday, or get Aunt Rosie’s famous chili recipe. Whatever it is, follow up with a call at the appointed time.
• Ask her when would be a good time to call, because you don’t want to bother her. Uncertainty as to when to call is one of the big reasons that many connections get lost. If she doesn’t give you an actual day and time, just ask her, “How about Wednesday at about 8 when I’m leaving the gym?”
• Text. Anytime is fine and a text is never a bother. Just tell her thanks for an interesting evening, check to make sure you wrote down the number correctly or wish her sweet dreams.
Most girls don’t hand out their number unless they want to hear from you. Don’t wait until she writes you off as just another guy who loses interest as soon as she’s out of sight.