Overuse of Punctuation
Excess punctuation should be left out of most sentences on the web. If a reader sees a sentence with more than one comma, the sentence becomes harder to scan and therefore more likely to turn a reader off. More advanced punctuation such as semi-colons and colons should be avoided completely by starting new sentences instead.
Wrong: “It is really important to keep three principles in mind, when thinking of the best shoes to buy; comfort, style, and eco-impact.”
Right: “Comfort, style and eco-impact should be kept in mind when thinking of the best shoes to buy.”
Short, sweet and no semi-colon.
Follow AP Stylebook. In a series of three, use only one comma. Example: There are nursing, automotive and computer students in the hallway.
Capitalize Words in Headlines/Titles/Headers/Subheaders
Excepting prepositions (of, to, for, etc.) and the words "is", "and" and "the," all major words in a headline/title/header/subheader should be capitalized.
One Space After a Period
The convention for web writing is one space after a period.
Don’t Begin Sentences with “But”, “And”, or “Yet”
This is more common than you would think. If you are challenging a concept from the previous paragraph or sentence, you may use “However” to start the sentence. If you are trying to follow up on an idea from a previous sentence, don’t begin a new paragraph and just present the idea in the next sentence. Your audience will leap with you without an introductory “and” or “but”.
It’s Versus Its
This is a very common mistake that a lot of people make. "It’s" is short for “it is”, so “it’s all relative” is correct while “it’s color is blue” is not. “Its” is a term of possession, so “its color is blue” is correct.
Overuse of “Also”
”Also” has its time and place, but frequent use looks like a grammatical hiccup and is highly noticeable after a while to your reader.
Keep Sentences Short
A sentence should never be longer than a line. If you need to list something, do it with bullet points rather than producing a long sentence.
Their, There, and They’re
Their: Is a term used to illustrate possession, such as “their mitts were soaking wet”.
There: Indicates the whereabouts of something, such as “the statue is located there”.
They’re: This is a contraction of “they are”. “They’re going to the beach today.”
Then and Than
These words are very commonly misused. Then is indicative of a place in time, such as “there was no internet back then”. Than is a quantitative term, which can follow the use of “more”, such as “there is no more annoying thing than a writer telling people how to write.”
When you are considering whether or not to use an apostrophe, look at your demographic. If you want your content to sound professional and authoritative, it is best not to use contractions.
Personal email: “You’re gonna find the new SEC regulations hard to navigate without a little help.”
Writing for the Web: “You may find the new SEC regulations difficult to navigate without some assistance.”
Wrong Acronym Use: “CPIC, CSIS, and the PAO are running a joint venture to better educate the public about how hard drugs finance international terrorism.”
Right Acronym Use: “The Canadian Police Information Centre (CPIC), the Canadian Security Intelligence Service (CSIS), and the Police Association of Ontario (PAO) are running a joint venture to better educate the public about how hard drugs finance international terrorism.”
Make Use of Headlines/Headers
Ideally, any site page or blog posting should read much like this article, with a headline/header and then a paragraph or two.
Headlines act as important signposts for the reader to decide whether or not they want to read those paragraphs, so the headline should always describe the subject matter of the paragraphs which follow it. This will look weird to those used to more conventional forms of writing, but the more you break it up, the more readable it is.
Use Spell Check and Your Eyes
Spell check isn’t always enough. If you spell “breakfast” as “break fast”, the typical spell check will not pick up on your mistake. This is especially important for website copy. You can’t expect people to trust your content if you have spelling mistakes on your page.
You want readers to be able to interact with your page. Use links to other areas of the site to make it easier for users to find what they are looking for.