1. Don't skip the cover letter completely. Writing nothing but "2000 words" says to me you don't much care about the submission.
2. Don't include details about any pets in the cover letter. I don't want to know about your cats, dogs, chickens, etc--even if sounds funny when you write it.
3. Don't include a synopsis of the story.
4. Don't include a title page.
5. Don't lie about the word count or "forget" about it when it is too long.
6. Don't include a "copyright" notice in your story.
7. Don't use some huge font for your story title.
8. Don't waste your first few paragraphs. Show me it is a story I want to read right away.