How do you flirt with a girl discreetly?

To flirt discreetly with a girl, maintain light eye contact and offer genuine smiles to create a connection without being too obvious. Use subtle compliments about her style or interests, and engage in playful teasing to keep the mood light. Additionally, find opportunities for light physical contact, like a gentle touch on the arm, to express interest without making it overt. Remember to gauge her reactions and respect her comfort level throughout the interaction.