If you want to sell more of your writing in the coming year, it's worth spending a little time thinking about how to make it more appealing. One strategy is to ADD something. Here are some examples:
1) Writing a non-fiction book? ADD a website that adds value to the reader (as I've mentioned, this is my strategy for the book I have coming out next year).
2) Writing an article? ADD photos the editor can use. Of course it's best if the photo relates directly to the article--that is, if it's a photo of someone or someplace featured in the article. But in some cases, especially when dealing with smaller, lower-budget or online publications, it can also be helpful to offer a more generic image that you've purchased from one of the stock photo sources (e.g., iStock). They offer images for between one and ten dollars--but double-check their 'approved uses' clause to make sure that you're not exceeding your rights and let the publication know the situation. For online publications, pictures with a resolution of 72 dpi are fine, but for pictures that will be printed, the resoution should be 300 dpi and the file should be CMYK, not RGB. If these terms don't mean anything to you, do a bit of research via Google regarding photo resolution and digital photo files.
3) Writing a poem for publication? Again, if the magazine uses images as well, sending one (letting them know you have the rights to use it) may help. Make it clear that you're just offering this in case they want to use it, not that you expect them to use it.
4) Writing a blog? Add sound or video files from time to time, to make it more appealing. Ideally, use these media for information that would be hard to get across with just text. For example, for New Year's, I've made a one-minute slide/music "card" that will be on this blog as of December 31, to wish you a happy new year.
Screenplays are the exception--generally you shouldn't add anything to it, as adding merchandising ideas, or graphics, or pretty much anything else marks you out as an amateur. The only thing they may want (and usually they'll say so) is a one-page summary. But in all other cases, it can pay off to brainstorm what you can add.