When would be a good time to approach a girl?

I'm a Freshman in highschool and so is the girl that makes repeated eye contact almost every time I see her. I want to approach her tomorrow but the problem is I almost never see her alone. she is ways and I mean always with her friends. Should I try and find her at her Locker or something is that a good place. I'm not afraid of talking to her at all I know what to say but I just can't find her by herself can anyone help?