As someone who has 5 hot girls half his age texting him at this very moment, all but one of whom initiated tonight, most of whom just gave me their number in the past week, and one of whom I spent the weekend with, I've never once asked them out in the first text. That's ridiculous. She might not even have you programmed in yet.
You have to start a conversation and learn something about them. By the time they give you their number, they should already be interested. You're only trying to amplify it.
You need to get them in the habit of initiating text conversations with you. Then ask them out within the first 10 texts or so (meaning she wrote to you 10 times).
The key is: send one or two texts, and wait until they reply. Don't have a rule about only one though. I just got a gorgeous waitresses number Sunday, age 25. I texted her Monday and she didn't reply. I texted her again tonight and now she's sending me pictures of her cats (always a good sign).
You must be interesting. Saying "let's meet for drinks" in the first text is not interesting. Telling them you just made crab cakes from scratch and telling them the ingredients is interesting. Telling them you visited 6 states since you last spoke is interesting. Try to let them send the first AND last text per day if possible. Respond to what they wrote and play their own words back to them. Keep your language positive (avoiding words like sorry, can't, and hate). Get them to send you non-selfies of themselves. Only send a photo of you upon written request.
That said, I've never once in my life used a smiley face or (laugh out loud acronym). Those are indeed highly feminine. But the winkie is the international "I'm only joking" symbol and being someone who is blunt, I've had to use this one. People often don't get humor over text, and it's the shortest way to say you're joking. It also doesn't sound apologetic. No other emoticons are ok IMO.
And for the love of God don't say BOOM.
