Research languages taught at your college and construct a plan. Before learning a number of languages, you will need to make sure that the resources for learning these languages are available to you. Decide which languages you wish to learn and in which order. Once you have an idea of what you want to study, and once you are sure that resources are available to do so, you will be prepared to better address specifically how to learn each.
Choose the right program of study. Many colleges and universities have modern or ancient language programs, or international business or politics programs, that have language requirements. Choosing programs such as these will give you a chance to learn new languages while studying a particular subject and will provide you with resources for learning the required languages. Some history or literature programs, such as classics or French literature, will also expose you to different languages, but these often include fewer languages than international studies programs.
Supplement your course learning. Luckily for language learners, there are a number of resources available on the Internet and at bookstores to help learn foreign languages. "How to speak/write/comprehend" books are common and available for many languages, as are software programs such as Rosetta Stone or Transparent Language. Another way to supplement your learning is to form or join a language study group. Meeting with others on a regular basis is a helpful way to ensure that you are regularly practicing the language.
Take a trip. Another great thing about college is that it often provides you with significant time off. Spring break, summer vacation, Christmas; all of these are great times to book a flight or hop a bus to a location where they speak one of the languages you are learning. Many colleges and universities have exchange programs to other institutions throughout the world, which are great ways to practice a new language while also receiving academic credit. Another approach is work or volunteer trips, which are often offered through your local travel agency.