Just say hi, be genuine, and if you elect to make a compliment as your first interaction keep it non-sexual.
Pickup lines are useful for online dating apps but if you have the courage to approach a woman in-person you're already ahead of the curb and there is no reason to use a pickup line. If you're genuine, and the woman is single, open, and warm hearted you'll be fine. Just takes practice. It's a numbers game, really.