Remember that English varies depending on which country you're in. For instance, U.S. English differs from UK English in terms of spelling, slang and word usage. Consider this when deciding where you want to study abroad.
See if your school or university offers a study-abroad program in an English-speaking country. You will not only improve your language skills, but you may be able to fulfill a few of your course requirements as well.
Sign up for an intensive language course abroad. This is a particularly good option if you do not want to spend a long time away from home or are looking for a bit of structure. Websites such as Sprachcaffe offer short English courses in England, the United States, Canada and Australia. Some programs also include sightseeing tours and cultural events.
Apply for an internship in an English-speaking country. Your university may offer internship opportunities, or check out a company you're interested in working for and see if they take international applicants. Doing an internship can improve your speaking skills and help you to pick up on practical, business English. You will also acquire valuable job experience that can make you stand out to future employers.
Consider coupling a study abroad course or internship with a homestay. Eurolingua, for example, offers this opportunity with their programs. This is an excellent and fairly non-intimidating way to immerse yourself in the English language and to experience the traditions and home life of your chosen country.