Read books.
That helps IMMENSELY.
Try Isaac Asimov (hes dead, but he did write over 700 books). Just grab ANY book from Asimov, I garantee you'll like it. Amazon should have them.
You can also grab the Game Of Thrones books. It helps if you have watched the TV series, so you have an idea on whats going on, and it also helps your vocabulary. And with books you begin to think in English - it get tiresome to read and translate and assimilate. Easier to simply read and assimilate.
If you'r into Science Fiction, try grabbing some "Battletech" books - they are great, and with a Sci-Fi Universe thats so coherent that it makes Starwars look like it's been written by toddlers.
Of course, it helps that Portuguese is a much more complex language than english... (our verbal conjugations are like the french ones - 6 persons (I, you, they, we you(plural) them) times a gazillion verbal tenses (4 past tenses, 3 future tenses, 5 presents). And all the verbs are what the english call the irregular verbs. Those are the normal ones. Then we got the irregular verbs (to be, to do, to have, etc) that have no easy way to figure out what word to use.
So yeah, English is very easy to learn after that.