1) Too certain statements like ALL, ONLY, EVERY, ALWAYS, IS TO BE.. cannot be answers. Unless these words are used in the passage, we cannot conclude with these words.
2) Words like 'CAN', 'MAY', 'FINE' will make the option positive to fit as an answer.
3) Concentrate on CONJUNCTIONS. They build the tone of the passage and also the relationship between paragraphs.
4) Link all the paragraphs to the main idea of the passage. Question yourself how can a particular paragraph contribute to the main idea of the passage.