Hey man, what I do is when I get their number is this.
Text a little while later after you get the number.
"Hey (nickname)
Its (name) im just shootin you a text now so you have my number. We should totally grab lunch sometime!"It goes straight for the kill about a day 2, which is good because if it works it works, if it doesnt it doesnt...no time wasted.
This way works pretty dang well for me so far. I did it three times tonight and already have two day 2's set up.
Ill usually get the response "Im so glad you texted me! I would love to go grab lunch!"
Cheers man.