Attend free classes. Organizations including Literacy Volunteers of America and Literacy Works host free classes for immigrants and anyone wishing to improve their literacy skills. Classes are usually held in community centers, public libraries or one on one with tutors at an agreed upon location. Local public libraries, community colleges and church-based organizations like English as a Second Language Ministries provide ongoing grammar and conversation classes. Students are usually not required to register, and can attend on an as-needed basis.
Check out audio-visual materials. Conversation helps, but it is important to drill phonetics and tenses. Local libraries carry English lesson CD's, tapes and DVD's that give you the convenience of planning your lessons whenever it's convenient for you. Companies such as Berlitz and Real-English offer audio-visual materials that introduce the rules of grammar and include re-creations of practical situations to let you see them in use. Repetition allows you to commit them to memory before they become a part of your vocabulary.
Join a language exchange. If you're new to the country or aren't comfortable in a group environment, consider a language exchange program that matches you with native speakers. Websites such as MyLanguageExchange and ESLmeetup give you the choice of face-to-face meetings or chatting online via instant messaging or Skype. Membership is free and open to all ages and proficiency levels. If there is no established group in your area, you have the option of starting one.