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.
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.
Also within a sentence, correlative conjunctions are used to establish relationships between parallel elements. The conjunctions either/or, neither/nor, and whether/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, next, finally, last, another, other, then
To signify a comparison - likewise, similarly, in a like manner, in comparison, so it is
signify a contrast - however, nevertheless, still unlike, in contrast,
conversely, on the
contrary, on the other hand, whereas
To signify a cause-effect relationship - therefore, thus, hence,
accordingly, in conclusion, as a result
To signify an example or specific meaning - for example, for instance,
to illustrate, for
one thing, frequently, in general, in particular, namely, usually, specifically
To signify a summary - to sum up, to summarize, in short, to conclude,
in conclusion, on
the whole, in brief.
TRAIN OF THOUGHT
A full sentence is not always a full idea. It usually takes more than one sentence to develop a train of thought. Links in a train of thought include such words and phrases as conjunctions (and, but, so, therefore, because, once, still), pronouns (he, they, both), demonstrative adjectives (this, that), adverbs showing how things are related in time (once, then, later), in space (upward, downward, around), or as cause and result (as, as a result, because of), and synonyms that rename. Sentences may be linked in a train of thought by many words and phrases such as those listed below.
as a result
on the contrary
on the other hand
so much for
to sum up