Ok a good rule is if she takes longer to respond back than you do to her, respond back in at least the amount of time it took her to respond back to you. You can even take the time and multiply it by 1.5 if you want. Say she took 10 minutes to respond so you take 15. She took 12 hours her next, then you take 18 ect. But there's no strict rule, just don't text back "instantly" like within 30 sec of receiving each and every one of her texts.
It's what you say in your texts that are more important.
If I were you I'd take her for wings then try and either go back to your place, a movie, or somewhere where you can do kino and cold routines with her and move in for a possible kiss.
Here's a texting game guide:
http://www.sendspace.com/file/znut0u