Focus on grades. That is 50% of your application. Pick an extracurricular you actually enjoy, and then excel at it and stick to it. Longevity and leadership is highly valued. It's better to have 1 solid extracurricular than 10 where you did not do much. You will stick out as the applicant who is a master violinist, captain of the varsity team, editor in chief of the college newspaper, president of the student body, executive editor of the undergrad science journal, student researcher with 3 publications