A common and sometimes fatal mistake for beginning writers is a failure to neglect the presentation of their work. We all know you shouldn't judge a book by it's cover as it's what's inside that counts. As Bollo from the Mighty Boosh once wisely said, "It's not the peel but the banana."
But manuscript presentation really counts and is really important. A manuscript needs to be formatted so that it is not only easy to read but also to annotate by your readers who may possibly be competition judges, agents or publishers.
If done correctly your work will stand out immediately before it has been read if it looks professional.
See below for a really useful post on manuscript presentation that features an example of a perfect manuscript presentation. I advise you to print it out and keep for future reference.
Hope it comes in handy :)