Coherence in a paragraph is the technique of making words, phrases, and sentences move smoothly and logically from one to the other. In other words, the ideas are so interwoven and "glued" together that the reader will be able to see the consistent relationship between them.
It is obvious that if a paragraph is not unified, does not have a logical order, and does not have a consistent point of view, the reader is unlikely to grasp the point of the paragraph. In addition, there are other devices and techniques that will help you achieve coherence.
In general, the coherence devices most helpful for making your communication clear for the reader are transitional words and phrases, repetition of key words and phrases, pronoun reference, and parallel sentence structure.
TRANSITIONAL WORDS AND PHRASES
One of the most common methods of establishing coherence in a paragraph is the use of transitional words and phrases. These devices indicate to the reader the specific relationship between what was said and what will be said.
Coordinate Conjunctions
Within a sentence, the coordinate conjunctions provide a coherent link to indicate relationships between parallel elements. The word and indicates a comparable idea; but and yet indicate a contrasting idea; or and nor indicate an alternative idea; for indicates a reason for a result already stated; and so indicates a conclusion from reasons already stated.
Correlative Conjunctions
Also within a sentence, correlative conjunctions are used to establish relationships between parallel elements. The conjunctions either/or, neither/nor, andwhether/or (not) are used to indicate parallel alternatives. The conjunctions not only/but (also) and both/and indicate parallel similarities.
Words and Phrases That Indicate Specific Relationships To signify an additional idea - also, moreover, again, further, furthermore, in addition, likewise, too, first, initially, second, third,