How can I keep a good conversation going?

[Dallas]

My friend told me this girl was into me. So she gave me her number and I waited 3 days to text her. But we talked on twitter still. But when I just texted her it was really dull replies. But on twitter we talked and talked and talked. The text convo lasted 10 minutes then I stopped replying. Why is this? I wanna be able to keep the convo going but I just can't. We're into the same things really (drugs, not hard, just weed, shrooms, ecstasy, drinking, and cigarettes). She's going to a party now so I'm gonna text her tomorrow but what are good things to talk about? I am 17 and she's 16. Best answer gets 10 points thanks And she's DTF so how could I, I guess "spit game"?