what the beast country to practice or learn English ?
(Not a teacher)
With the right attitude and dedication, and of course practice, you can learn any language in any country! Finding a tutor/class/language school would help a lot too.
There's no doubt that being in a country where the language is used by natives or extensively is a great benefit - you are learning through necessity if you do this. There isn't an English speaking country where this would be better to do than any other English speaking country. However, it's hardly ever a plausible idea to spend months or years in a foreign country.
Don't just stick to books and exercises either. Try and listen to songs in English, read English books - even if it's children's books, they are great for new vocabulary, watch tv programmes/films, listen to the radio. Most, if not all, of those things you can do on the internet. The internet itself is a great resource if used wisely!