Momentum involves giving the reader adequately developed and reasonably arranged material for a smooth ride.
Rereading your own prose will not always disclose gaps since you may unconsciously fill them.
The Devices of Momentum
Make sure that a strand of an idea runs through the paragraph and the composition.
Use recurring images associated with the idea in separate sentences, e.g. insects, ant-heap, swarm, etc.
Use repetition, but be wary if it becomes monotonous, e.g. I have a dream
If repetition seems monotonous, use a reference pronoun, e.g. it, but make sure its antecedent is unmistakable
Incorporate minor variations, e.g. contemporary music, listener, eclectic listener, musical taste, broad-minded listener
But be wary of near synonyms that may confuse the reader, e.g. device, instrument, mechanism, etc.
You can use the connection between question and answer, e.g. Stop! What? That!
A pro-con series is useful for controversial subjects, e.g. But… We do not… Most people assume…
Incorporate parallelism to establish a rhythm for your readers
Transitions
While a word may do for two paragraphs, a sentence or even a full paragraph is needed to join larger sections
Develop a large vocabulary of connectives & conjunctions. Use them precisely.
To introduce an addition: and, also, next, in addition, besides, finally, last, furthermore, moreover, likewise, similarly
To introduce a contrast/qualification: but, however, yet, still, in spite of, in contrast, on the contrary, on the other hand, nevertheless, at the same time, though, although, of course, after all
To introduce a summary: then, thus, therefore, consequently, hence, to summarize, to sum up, in short, in brief, in conclusion, as a result
To suggest passage of time: immediately, soon, while, until, presently, shortly, thereafter, afterward, in the meantime, meanwhile, lately, since
To introduce an example: for example, for instance, thus, to illustrate, in particular
When numbers are placed mid-sentences, they are unobtrusive, e.g. Poetry is characterized, second, by its emotional content
The transitional paragraph is brief: This is what I’ve been talking about; this is what I’m going to talk about; and this is how the two relate.