A mutual friend girl that I have never met added me on snapchat. When I talk to her should I flirt and what kind of things do I say?

It's best to start by getting to know her a bit before diving into flirting. Keep the conversation light and fun by asking about her interests, hobbies, or mutual friends. If the vibe is positive and she seems engaged, you can gradually introduce some playful teasing or compliments. Just be sure to gauge her responses and ensure she's comfortable with the direction of the conversation.