Attend a high school or college class that teaches reading, writing and speaking English. If you don't want to enroll in a full college program, many colleges offer--through their adult/continuing education programs--extension classes that provide beginning and advanced instruction in English as a second language.
Sign up for a class that best represents your current level of English reading, writing and verbal comprehension. If you are learning English to fulfill an educational requirement or to be eligible to attend a university in a primarily English-speaking country, you will normally be required to pass one of several approved tests like the TOEFL (the Test of English as a Foreign Language). Contact an admissions counselor at the school you are interested in attending for more information on language proficiency requirements and exams that satisfy the requirement.
Choose a different approach if you don't have access to or the financial resources to attend classes, or if you need to learn English for an upcoming business or personal trip. Check out free library videos, tapes and books that offer instruction in English. Alternatively, you can simply buy tapes, videos and programs (including learning games for children) that can help you learn how to speak, read and write English.
Practice with the material you are using until you feel proficient. Quiz yourself or ask someone else to quiz you by placing words and phases on note cards with the answer in your own language on one side and the English translation on the other side.
Practice with someone who is a native English speaker and also speaks/reads/writes in your language. This could be through conversation, emails or letters. For example, use video conferencing as a means of having a conversation with an English-speaking friend in another country.