If she goes to college, will it be for dance? I don't have experience in the arts, but if she goes for dance, there will be auditions in addition to the regular college admission process. If she wants to get into a top school, she needs to be really, really good - not being good on a local/regional level, but being good on a national level.
If she doesn't want to go to school for dance, she should probably have some other ECs. Maybe something academic, like math team, quiz bowl team, Model UN, debate, etc. Being a part of student government is another good EC. Community service is big too - tutor younger kids, help out at a soup kitchen, etc. She needs to choose which ECs appeal to her.
Even if you do all of this, being "well-rounded" doesn't help much at the elite schools. If you can't do something well enough to be recognized at the national level, then best to do something really unusual (but best if you are passionate about it - not just something for college apps).
My eldest is a college freshman and she didn't get into any elite schools (waitlisted at one). She had pretty good grades, good SAT & ACT scores and was well-rounded, but there are tons of applicants like her.
If she lives in an area like ours, there are plenty of college consultants to guide you (for $5K). They start in 8th grade and plan your high school courses, ECs, etc. She should be able to figure out on her own what she needs to do. She can read posts on College Confidential if she wants to find out more about the admissions process. Good luck to her.
