Mistakes are easy to make when you're in a hurry and rely on spell check to catch your mistakes. You probably realized that the last time you typed "two" when you meant to type "too." As long as the spelling is correct, your computer is happy. Proper usage is up to you.
Do you remember somewhere around fourth or fifth grade when your teacher introduced you to the concept of homonyms—words that sound alike and/or are spelled alike but have different meanings? Sometimes you grab the wrong word from your memory bank because it truly is a homonym; other times, while the words are not actual homonyms, they share a close enough connection to be confusing. On that note lettuce (oops, I mean let us) take a look at some commonly confused word pears, eh, word pairs, that is.
Are you clear on your contractions?
Who's is a contraction of the words "who is" or "who has."
Whose is used to ask a question such as "Whose dog is this?"
Its without the apostrophe indicates possession by an inanimate object—"That flat tire has lost all of its air."
It's is a contraction of the words "it is" or "it has."
You're is a contraction of the words "you are."
Your is the second person possessive determiner, as in "Is this your work?"
Here are a few pure homonyms that are sure to make most people stop and proofread their work.
Stationary means something is not moving or not changing.
Stationery refers to paper and/or other writing supplies.
Shear means "to cut," as in the wool off a sheep.
Sheer commonly refers to something that is very thin.
Principal means first in order of importance—remember your school principal?
Principle, on the other hand, is a system of thought or belief.
Grisly means causing horror or revulsion.
Grizzly refers to the (Grizzly) bear's white-tipped fur.
Discreet is to be careful not to attract attention or give offence.
Discrete things are separate or distinct.
Council is an administrative or advisory group.
Counsel refers to advice or guidance.
These last two are close enough to be confusing although not true homonyms.
Ordinance is an authoritative order.
Ordnance refers to guns or munitions.
Loath people are reluctant or unwilling.
Loathe means to dislike greatly.
Mastering the sound-alike words is just the tip of the iceberg when it comes to writing well. And remember, there is no shame in owning a dictionary; if you are really in a hurry, try the 'Thesaurus' button right next to spell check.