When I was young, I chose to work before I completed my degree and go to school nights. This helped me to focus what I studied with the knowledge of what was being done in industry. I studied computers and control systems in 1959, before most people had ever heard of them. If you could work for a company active in your field of interest for a summer, you would learn what subjects you need to concentrate on in your next year. When you graduate and fill out applications, it really helps to know some names of people to send it to.
Contacts are very valuable.
Student organizations often have speakers from industry where you can meet people and ask them questions. In school, unfortunately, you are often taught by teachers who specialize in academia, not business. I remember taking a project management class from a professor in my Engineering Executive Program years after I had to learn to do project management by doing it. We had a lot of disagreements, and I was very glad I had the real world experience to compare his words with. Interning gives you that touch of the real world.