Read the competition's rules and heed them carefully. The judges will have a lot of stories to read, so the cleaner your manuscript is, the better. If you're not sure, we'll be putting a sample document on the website in MS Word format. Download this and use it as a template. Check the spelling and punctuation at regular intervals.
Poor spelling reflects badly on the story and the author.
Ellipses have three dots, no more, no fewer. There is no space before a comma. If you don't know how to use semi-colons either look it up or don't use them.