It is impossible to memorise every new word you find when you are reading. Vocabulary is a difficult area of any language. One good idea is to learn a whole sentence containing an important word.
For example, the Portuguese word "camisa" translates to "shirt". Instead of just trying to remember the word, try learning the sentence "I have a blue shirt and a black tie". If you learn the sentence in context (clothing) you are more likely to remember the meaning.
To help you remember the rule about adjectives and plural nouns, remember "I have two new shirts". This will help you remember "shirt" and also that a plural noun ("shirts") takes "new" (not "news").
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