Again the best technique is to practice more. As your general level of English increases so should your reading. Do not be afraid of new words, but try to understand them from the context. That is where flexible thinking comes in. Then made a note of them in your vocabulary book .
First skim a text, to get the general meaning. Then read it again slowly and precisely. If you try to read too fast you might miss important words like "not".
In English, there are many words that look very much like their counterparts in Portuguese.
NOUNS ção -> tion
intuition , revolution , action , intention
NOUNS dade -> ty
entity; fraternity; velocity; identity
NOUNSador -> tor
elevator; computer; calculator ; inventor = inventor (an exception)
ADVERBSmente -> ly
really; properly; easily = facilmente; traditionally
Read the text and see if you can fill in the blank words by understanding the context