As a college student, the best way to get started in accounting and finance is to take an introductory accounting course. Typically, this course would be called 'Principles of Accounting' at most colleges and universities. Some institutions break up the course into Principles of Accounting I and Principles of Accounting II. Take this course (or both if offered) as early as you can in your undergraduate career. This allows you to see if you enjoy the subject and if you can handle the content. Additionally, take an introductory finance and business course to get additional exposure to business.
Other prerequisites normally required for an accounting major would be Principles of Economics I and II. One course focuses on microeconomics, and the second course focuses on macroeconomics. Both of these courses are typically taught at the introductory level. Finally, you will need a calculus course and a writing course to round out the prerequisite requirements as most colleges and universities.
Once you enroll in these courses, please work as hard as you can and do your best. If an area doesn't make sense, please take your time to read the content carefully, work the problem sets, review answers to practice problems and go to office hours. These courses form the foundation for the rest of your accounting, finance and business studies. It is critical that you have a firm grasp of the introductory content. Specifically, a strong understanding of basic accounting will allow you to comprehend more complex topics you will encounter as you advance in your degree.
Outside of you formal coursework, please consider joining business-related groups during your first and second years as an undergraduate. For example, there could be an investment group at your college that you can join. There could also be case competitions you can enter either individually or with a group. These would give you additional experience in the field that you can use towards your resume when looking for internships.
As you near the end of your second year and especially in your third year, start attending career fairs, networking events and information sessions with companies that recruit at your school to learn about the different opportunities available at their firms and start applying for internships.