RC has a thread about text game. I think it's in his signature. He's active enough on the forum and I'm sure you'll find him.
One tip I'd give: Don't make this the only girl you're thinking about. I can tell that you already are, because you're so invested. She invited you out. Assume she did it because she wants you - women don't like making the first move, she tried and you didn't come. She's tried twice now. How about you man up and text her "Wish I could have made it the other night! When are you free? Got a cool place that I want to show you" or something similar. When she tells you, set a definite date to the point that you'll have no need to text her further (doing so will just increase the chances of her cancelling)
If she does anything other than agree to a definite date, just say "Ok well give me a call if you change your mind" OR "Well when you've figured out your schedule let me know and we can do something cause I'd love to see you" and leave it at that until she texts you again.
Focus on other women, too. Don't be so selfish.
Edit: Here you go:
closing-and-day/topic189023.html