One of the things most people take for granted is that a writer will be able to use proper English. Yet, especially today – when anyone can spend the money to publish anything they write – we see that this is not exactly the case.
Many beginning writers feel that they don’t need to spend a lot of time learning the basics of language – things like proper spelling, grammar, and punctuation. However, the truth is that not using proper English brands you as an amateur instead of a professional, and tells your readers that you’re just not interested in working to produce a professional product.
Don’t be that sort of writer!
Take the time to learn the rules of the language. Spell-check can only do so much, so you need to understand which word you should actually use in a given situation. There are a couple of good lists of common errors HERE and HERE – check them out and be sure you don’t get them confused yourself.
Another error is the use of the common apostrophe. Learn how to use that correctly, because there’s nothing that screams ignorance like a misplaced apostrophe.
There are plenty of good English books out there that will easily teach you the basics of the language. You might also peruse Strunk and White’s The Elements of Style and Brown’s Self-Editing for Fiction Writers.
The important thing is this: unless you have a firm grasp of the basics, you’re not really going to be able to bend those rules to create a unique voice for yourself.