The body of the letter should be divided into as many paragraphs as
there are distinct subjects in the letter, or a new paragraph should
be commenced at every change of the subject. The habit which some
persons have of tacking one subject to the end of another, and thus
making a letter one continuous paragraph of mixed up information,
instructions and requests, is extremely objectionable. It destroys the
force of what is said, instead of fixing each thought clearly on the
mind of the reader; it leaves him confused, and he reads a second time
and tries to get his ideas fixed and systematized, or he throws aside
the letter until he has more time in which to study it and get the
meaning clear.

If the letter is long and is really concerning only one subject, then
it may properly be divided into paragraphs by separating the different
divisions of the subject, and giving a paragraph to each. These should
be arranged in their logical order. Wherever the letter is to contain
numerous paragraphs to avoid omitting any of the items, it is best to
jot them down on a slip of paper, then embody them in the letter in
their natural order.

The first word of each paragraph should be indented, or moved in from
the margin, usually about the width of the margin. Thus if the margin
is three-fourths of an inch in width, the paragraph should begin
three-fourths of an inch from the margin. Some writers, however,
prefer to commence the first word of the paragraph an inch from the
margin, and it is really not so essential what the distance is, as
that it should be uniform, and all the paragraphs begin alike. A
little attention is necessary here. In ordering goods make each
article a separate paragraph.