William Strunk Jr.

there may be no need of

The beginning of each paragraph is a signal to him that a new step in the development of the subject has been reached.

As a rule, begin each paragraph with a topic sentence, end it in conformity with the beginning.

you should be able to

he abbreviation etc., even if only a single term comes before it, is always preceded by a comma.

Exceptions are the possessives of ancient proper names in -es and -is, the possessive Jesus' , and such forms as for conscience' sake, for righteousness' sake. But such forms as Achilles' heel, Moses' laws, Isis' temple are commonly replaced by

the heel of Achilles

the laws of Moses

the temple of Isis

The pronominal possessives hers, its, theirs, yours, and oneself have no apostrophe.

In the names of business firms the last comma is omitted, as

Brown, Shipley and Company

The abbreviation etc.,

The abbreviations etc. and jr. are always preceded by a comma, and except at the end of a sentence, followed by one.

The Elements of Style