As mentioned already, humor and a little cash are always nice. Like I have mentioned main times in life, "Money isn't the answer to everything, but it isn't any fun being poor."
Girls like a guy who is genuine, attentive, and caring. Flattery is usually not a bad idea. If the girl your into doesn't reciprocate that, then you might want to look elsewhere.
Hell I had a date Friday & Saturday with a lady that was absolutely beautiful and I'm still amazed she has already accepted another date.