Never use exclamation marks.

Avoid using ampersands outside brand names, trademarks, formal titles, or in logotypes, (e.g., Ogilvy & Mather, Standard & Poor).

Use % when dealing with numerals. Use "percent" when the numbers are written out.
Example: 5%. 10%. The stock is up five percent on the month.

Not 24x7

No hyphens

Verb, to influence
Effect - verb, to cause; noun, result

Two words

Among introduces more than two items, between introduces two items.

Hyphenated

One word. Do not use AV as an abbreviation.

Sophos appliances (but Sophos Email Appliance/Sophos Web Appliance)

Example:
PC-based

Not BlackBerries or Blackberry

Use in preference to block list.

A compliment, with an i, is a kind or flattering remark. If a friend says he likes your new shoes, he’s giving you a compliment.

A complement, with an e, is a full crew or a set, and when something complements something else, it means they go well together. You might talk about a picture frame that complements a photo or the crew complement needed to operate a ship.

Use zero day (no caps, hyphen if adjective); do not use 0-day.

Two words

Not data leakage

One word

Two words

No hyphen or caps

See affect

Write e.g. in lowercase and follow it with a comma. When giving an example, use e.g.
Use i.e. if you need to give further explanation (i.e., to explain a point you’ve made already in more depth).

One word, no hyphen

Noun

Adjective

Not EM

Write in lowercase and always follow it with a period

Not everyday, unless as an adjective

Capitalize

Not Fake AV, not fake anti-virus

Use farther to talk about distance, and use further to talk about time or amount.

Use less when you’re talking about things you can’t count individually; use fewer with objects you can count one-by-one.

One ‘s’

Not 4-color process

If preceding a noun

See farther

Noun