
You don’t. You give her yours; you say “hey, been seeing you around and you’re cute. I’d really like to get to know you more if you’re open to it. No pressure” and you hand her your#, smile and walk away calmly if she doesn’t continue the conversation then and there. Some girls are shy and this take the pressure off them to perform. Some girls are less so and will be better at immediately engaging the convo. Regardless this signals the interest and opens the door, but gives them the power.