As with learning any language, the best way to learn English is to practice. Make it a habit to use English while interacting with your everyday surroundings. Immersion is ideal, but there are many ways to learn English without moving to a different country.
Seek out English native speakers. Those whose first language is English can provide learners with ways to produce natural-sounding English. Watching English language movies and TV, reading English newspapers and magazines and listening to English music helps learners develop their language skills and become informed about English-speaking culture at the same time. Keeping an English diary is a great way to improve English writing and gather practical vocabulary. Rote memorization is helpful, but the most effective way to learn English is to surround yourself with the language.