One of the best ways to practice speaking a language as English is simply talk and talk and keep talking as if there was no tomorrow. This ongoing effort to speak will become a habit and eventually you start thinking in English, the thought is no longer in your own language.
During learning, all teachers will tell all students that the only way to perfection through continuous practice. If you learn to speak English, then the best way would be to continue to practice in speaking, reading and writing. Here's how.
Speak, read and write. This is how you do it. No other way to Him. You just have to take it to the letter, you can not practice thinking your way through it, and you actually do it. You dream of practicing will not help improve your skills, especially English.
You, as the learner must understand that the English language is not a pure language when it is spoken. One of the purest language is Basque, and it is not English. English was influenced specifically by several other languages. The language we now know that English is not the language of Shakespeare, Wordsworth or even Chaucer. How do I know? Just read their works and you will see many different spelling, usage of words are also different and certainly the grammar is different.
When you talk to your friend in English, you will use the modern English, American, not British. Talk to your friends in English, even if they respond in your native language, just go ahead and answer in English. However, you must inform them of your actions or why they will feel that you are insulting. Once they know you're practicing, they will actually practice with you and even learn from you.
As you continue to talk, you should also learn from books and other media to help improve your grammar and vocabulary. To return to the classics, that you can possibly go after acquiring new skills. Once you have done one of the best ways to improve your grammar and vocabulary through the classics.