Submersion is usually the easiest way. Go to an American or British chat room where they also speak on video. That would be my suggestion.

There's no magic way around this. You simply have to work hard. That means taking in anything that comes your way, AND paying attention to your own errors. You will make (and have made) mistakes... so just learn from them. :) I agree with Candi and Xarmanla's suggestions.

Immersion is really the best way to learn. I think taking a class with others learning the language is a great way as long as the students and the instructor agree to communicate only in the target language.