If you start stuttering, look her in the eyes and say her beauty takes your speech away, or you are excited to be near her. Practice it though, don't stutter as it ruins the line. Also don't stutter as you are about to say yes to going back to hers, say "fuck it, nice knowing you" and just potter off embarrassed. Took me a month of begging for a second date. She found the funny side of though.