This site is a very good resource for learning English! (Even for free) Talk to English speakers on here and practice :) Watch English shows/movies with Portuguese subtitles :)

How to learn English? Buy course books! Contact a teacher! Go to night school! Watch English films (or American movies, or Australian ones, or Canadian, or Nigerian etc.). Check out grammar websites and podcasts. Listen to songs with English lyrics, and google the words. Most of all... TALK to someone. There are lots of teachers and students on italki. Other students can often help - for free!