Make sure you have fresh breath.

Was on the R train today on my way back from college and sat next to this cute girl on the train reading Life of Pi. I was reading a book as well, and as we were riding the train two guitarists came and we couldn't read cause the noise was loud so we both just looked at each other, put our books down, and laughed. This allowed me to initiate a conversation about Life of Pi, she asked what I was reading (showing interest) and she put her book back in her purse and we began talking until her stop. Anyways, the reason i'm mentioning this tip is because as I was enjoying a few tic tacs and talking to her about New York City, she mentions that a guy tried talking to her on the train a few days ago who had terrible breath to the point it almost made her gag, and she would have given him her number if he didn't have bad breath.

tl;dr make sure you have fresh breath before opening your mouth