Find a way to remove yourself from your native language. Set aside time every day to be alone in your room listening to English audio or video. Immerse yourself in English. For those learning in their native countries, this can be difficult. For those learning in America, it should be easier.
Repeat words and phrases multiple times. Speaking aloud in private gives you time to practice speaking what your hear. If you are listening to English music, sing along, out loud. Compare your pronunciation to that coming through the speakers, and work hard at making sounds that might be absent in your own language.
Spend time with American/English-speaking friends. Listening to English isn't enough. You have to speak it, too. Even if your English is full of errors, the act of speaking and carrying on a conversation, even if it's choppy, is good practice. You will gain constructive criticism and input from those who speak English natively.
Ask your friends to speak only English to you. Even in America, many international students struggle to separate themselves from their native languages. Far away from home, they tend to latch onto anyone they can find from their native country, and subsequently fall back into old patterns, especially that of speaking in their own tongue. Although a balm for homesickness, it hurts language acquisition.
Live in an English-speaking home for a while. If possible, this type of immersion is the best way to gain a complete understanding of the English language and learn accent-free speaking skills.