A cohesive text can be achieved by means of
　　* grammatical devices — such as tense and aspect, reference, substitution, time or place relater and parallel construction;
　　* lexical devices such as hyponymy, synonymy, complimentarity, and metonymy and repetition;
　　* logical connectors, such as "and", "but","in addition", "that is to say", "in the same way", etc.
If you are sensitive to these text cohesive devices while you are reading, you will understand the text better.