Take introductory classes you won't know if you like a major until you try out a class. Obviously you need to be judicious about this, as you don't have time to sample everything. Get relevant experience through internships, volunteer work, paid jobs, student organizations, etc. Many students are convinced that every career requires a particular major, but that is not the case. Very few of the thousands of jobs listed in the U.S. Department of Labor's Dictionary of Occupational Titles require a specific undergraduate background.
Employers are more concerned with the person they are hiring.
Note that this suggests that you choose a major that you enjoy and are good at. Become involved in campus and community activities. This demonstrates leadership, teamwork, and organizational and managerial skills. You might be better off with a part-time job that relates to your career interests. Acquire strong communication skills, both written and oral.