Цитаты из книги автора William Strunk Jr. The Elements of Style

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

The man whom he thought was his friend
The man who (that) he thought was his friend (whom he thought his friend)

Similar to this, but with even less justification, is the use of the plural pronoun with the antecedent anybody, any one, somebody, some one, the intention being either to avoid the awkward "he or she," or to avoid committing oneself to either. Some bashful speakers even say, "A friend of mine told me that they, etc."

Use he with all the above words, unless the antecedent is or must be feminine.

The people is a political term, not to be confused with the public. From the people comes political support or opposition; from the public comes artistic appreciation or commercial patronage.

Oftentimes, ofttimes.

Archaic forms, no longer in good use. The modern word is often.

Less refers to quantity, fewer to number. "His troubles are less than mine" means "His troubles are not so great as mine." "His troubles are fewer than mine" means "His troubles are not so numerous as mine."

When however comes first, it means in whatever way or to whatever extent.

However you advise him, he will probably do as he thinks best.

However discouraging the prospect, he never lost heart.

Place the emphatic words of a sentence at the end.

The relative pronoun should come, as a rule, immediately after its antecedent.

Formerly, science was taught by the textbook method, while now the laboratory method is employed.

Formerly, science was taught by the textbook method; now it is taught by the laboratory method.