Do Not Call1. DO NOT wait more than 3 days to call a woman you spent less than 5 minutes speaking with ("hitting on"). The reason you shouldn't wait to call is because you're going to sound pretty lame when you have to say, "I'm the guy with the shirt that said, 'I love cookies'", to remind her who you are. And you WILL have to remind her (whether she remembers you or not ) if she's a single woman that many men find attractive. You're probably not the only one she gave her number to that week or even that day.
2. DO call her between the hours of 7-9pm. This should be about the time that she's winding down if it's a week day or just before she's about to get ready to go out with the girls, if it's a weekend. This is not a booty call nor is it a play date. This is the age of the text message; you can use that to your advantage and text her first. It breaks the ice and you won't have to hear her say, "I'll have to call you back," if it's a bad time.
3. In the case that it's a good time, and she's texting you back with quick responses, DO NOT allow it to become a texting match. Quickly kill the texting and ask if you can call her or she call you (do not take it upon yourself to just call her up -- ask first). Getting her on the phone makes you come off as confident. And you're not one that needs texting as a buffer. You have balls. Besides, late night TALKS are more intimate than late night texts.
4. DO NOT stay on the phone with her all night, unnecessarily. It makes you look clingy. It also imply that she is already more important than your previous engagements. A person with a life as great as yours have things to do! I don't care if it's to get ready for work in the morning, to hang with the guys, or even to go out with the other girl you met last month. You just met this woman! Do not make her feel like she's anything more than a stranger you'd like to get to know.
5. And last but not least, if you can manage -- DO get off the phone with her first. It's even better if you do this while the convo is at its zenith (albeit, you were charming and had her laughing). It will certainly have her wanting more and waiting for your next call.
Disclosure: The above advice will NOT work for men with bad humor, no humor, boring conversation, rude remarks, and anything that defines you as someone with "no game".