Langauge Tips 2 - English (typographics, grammar, punctuation)

Most of the text below is from or based upon text in the Oxford English dictionary:

• Year and Time:

BC and AD instead of B.C., B. C. etc.
Also, write BC after the numerals, as in 42 BC.
Write AD before the numerals, as in AD 175, unless the date is spelled out, as in the fourth century AD.

a.m. and p.m. instead of AM, A. M., a. m. etc.

• Apostrophe usage:

The easy part -
Short forms:
he's, haven't, can't, don't, won't, we'll, '68, o' clock (of the clock).
Letters or numbers referred to in plural form:
Mind your p's and q's. Find all the number 7's.
Omit in MPs, 1940s.
Omit in plurals of a regular noun: three cats rather than three cat's.

Tougher -
To indicate possesion:
With a singular noun: boy's book, week's work, boss's salary
With a plural (s ending): a girls' school, two weeks' newspapers, the bosses' salaries.
With a plural (other than s ending): the children's books, women's liberation.
With a singular name: Abhijit's phone; Yashyas' (or Yashyas's) phone.
With a name ending in -es that is pronounced -is or -eez: Moses' mother
Omit in a business name: Grindlays Bank.

Only for the word its:
Use it's when you mean it is or it has. In all other situations, use its.

Also, a look can be had at: http://owl.english.purdue.edu/handouts/grammar/g_apost.html