Parallelism works because it creates anticipation in readers, who can see where the argument is going simply from the repetition of key words. Parallel structure works across paragraph boundaries too. Such repetition matters particularly in an oral setting, which is why Jesus used it and why today's politicians do the same. The heart of the sentence lies in its subject and verb. Choose both well, and readers will find your sense quickly and easily.
Stronger transitions link parts by their relation to one another.
Subordination links ideas through hierarchy. When you use subordination, you clarify the relative importance of your ideas. See chapter nine in Harbrace for more help on incorporating subordination into your writing.