Please don’t think it is necessary to put in an apostrophe every time a word ends in an s. Sometimes those are indicating plurals, not ownership. One dog; two dogs. One dog’s tail; two dogs’ tails. And, as you can see, in the plural, the apostrophe goes after the plural marker s. The Gregg book is also helpful about irregular plurals.

Spellings your spell checker will miss
When you use the spell checker on your document, remember it cannot tell the difference between there and their; here and hear; affect and effect; and to, too, two. You need to check these yourself. One way is to use the Find function (usually under Edit on the menu bar on your computer). It will display each use of the word you are checking, so it is easy to correct when necessary. Remember, you are the boss of the spell checker.

In Canada, we usually differentiate between practise and practice. Spelled with an s it is the verb and spelled with a c it is the noun. Think of this: I practise every day in my medical practice. I remember the difference by thinking of advice (the noun) and advise (the verb). These are easier to remember, because we pronounce them differently.

If you think correct spelling is not very important, it is. I have seen people struggling to read something I thought was fairly straightforward, only to find out that the problem was a spelling error. When you have limited literacy, you tend to blame yourself when you can’t read something, rather than realizing it is someone else’s mistake.

Subject and verb agreement
This is usually a simple rule. Subject (sometimes called the actor) and verb need to agree. The book is green; the books are green. We use a singular verb with a singular noun, and a plural verb with a plural noun.

If there are two subjects joined by and, they need a plural verb. For example, Janet and Annie bought new cars this year.

If there are two or more subjects, but each one has each, every, or any before it, use a singular verb, as in Each dog and cat deserves a good owner.

If the subject is either + a singular noun…or + a plural noun, the verb follows the nearest noun. So, in the sentence Neither the eagle nor the crows were interested in the roadkill, the verb is plural to go with the plural crows. But if we put it the other way around, we would say Neither the crows nor the eagle was interested in the roadkill, using the singular verb to go with the lone eagle.

A noun which stands for a whole group, such as group or family, needs a singular verb if the group is seen as a whole, but needs a plural verb if the members of the group are acting on their own. We say Is your family well? or Are your family all well? What we mean is Is your family [as a whole] well? or Is each individual member of your family well?

There is one difficulty which strains the rules: that is the use of general single nouns (called compound pronouns) like someone, and everyone. Even here the rule usually applies—a singular noun needs a singular verb. Here is an example: Someone needs to drive to Edmonton. Singular noun, someone, followed by singular verb, needs.