I generally try to text a girl immediately following a number close. Like I'll walk away, and within 30 seconds will text something like 'Who was that outrageously cute guy you were just talking too? He was AMAZING!' or 'Shit shit shit, I forgot to ask something really important: If you had to choose, would you rather be a fish or a duck' or something.

Just gets her used to the idea that its ok for you to text her. After an hour or so, she might have been chatted up by someone else, she might have forgotten about me, whatever. The text just puts me in her world when I'm not there as well.

Just a suggestion

Other than that, you're doing well man. Keep opening and keep closing!