Last week I was having a quick browse on eBay when something caught my eye. "Black patient shoes!" screamed the headline. "Must see!"

"Wow!" I thought. "Patient shoes! What are they when they're at home?" I clicked on the link. The shoes appeared. Black they certainly were. But 'patient'? No. Or not as far as I could see, anyway. These, you see, were patent shoes ? as in 'patent leather'. And very nice they were too ? just what I was looking for, and in my size. Did I buy them though? Not on your life. I didn't buy the "gorgeous sequence dress" I found a few minutes later, either. (Answers on a postcard if you can guess what a "sequence" dress is?)

My reasoning was simple. If the sellers of these items couldn't be bothered to take the time and care to make sure they'd got the name of the product right, and spelt it correctly, then how on earth could I trust them with the more complex matter of accepting my payment and sending out my patient shoes? The answer: I couldn't. The sloppy spelling had created the impression of a sloppy seller. It had also lost them a customer.

So it is with business. You may think that a couple of spelling mistakes in an email or report don't matter. They do. Just ask all of the prospective job candidates whose applications didn't make it out of the slush pile because their covering letter was littered with typos. They don't get an interview because they've already made themselves look careless; if your website is a mess of bad grammar and spelling, then it doesn't matter how great your product or service is - you already look unprofessional. And if your marketing literature is littered with mistakes? forget it!

Whether you're a large-scale business or a small-time seller, proofreading is something you really can't afford to skimp on. It's also something you shouldn't try to do yourself. As any professional writer will tell you, when you work on a piece of writing you become blind to its faults. No matter how carefully you re-read it, you see what you think is there. That's probably why last year a well known news website confidently predicted that John Kerry would "knot" win the US election. And why my accountant keeps writing to me about "teh business."

If you're serious about your professional image, get someone else to proofread your brochures, website, letters and adverts. And steer clear of patient shoes?

Amber McNaught runs Writing World, a new agency for freelance writers. Writing World provides a free agency service which helps writers find work, and helps employers find the best writer for their project.

Writing World also offers a range of service such as proofreading, edting and manuscript appraisal services to new and aspiring writers.

Visit the Writing World website at http://www.writingworld.org