At what point do you start telling a girl she's beautiful, cute, etc?

[Ryan]

In a way that doesn't seem like your chasing her, but to qualify her and let her know you're interested in her romantically.

 

[superomar]

Id suggest using the word cute, or utilizing a genuine compliment when opening, specifically with a direct opener. Other than that, I wouldn't use the words beautiful or such in the first interaction, or anytime unless shes given me a really genuine compliment. Also, you want to compliment things about her, without showing that you're actually chasing her. For example, "Your hair flows down so naturally, (lightly touch her hair at a high point) it's like silk between my fingers."