I have quite good text game but I'm trying to avoid it nowadays. Talking on the phone or in person always generate more attraction and rapport, saves time also. I had problem transitioning from text game to real life game because my real life frame isn't as strong as my text. Also the tonality plays an important part also. Girls can smell the inconsistency in it. That's why I'm trying to improve my real life game instead.
As for your question, just text her random unpredictable things. My favorite routine is the following:
Text 1: Pick one: [dinner entree 1] or [dinner entree 2]. Hurry up!
She replies
Text 2: [Dessert 1] or [Dessert 2]
She replies
Text 3: Pillow fight or movie under candles?
She replies
You get the idea, typically I only asked 3 questions. Depend on how much IOIs her answers are. I end it with the following 2 options:
Option 1: "Perfect. Be here at xxxx pm

" Then when she comes over, I have everything completely opposite to what she picked.
Option 2: "Thanks [insert nickname]" And don't reply to her for at least 2-3 days.