I found a magazine call for submissions that is driving me to try pitching to a magazine for the first time. The instructions ask for relevant clips, but my prior work is either fiction or IT tech documentation, nothing anywhere near the style they need. However, the article length for this outlet is short; I have multiple pitches in mind and I was able to bang out a draft for one of them yesterday. Can I use this for a clip?

In addition, I'd be interested in any general pitching advice for a newbie looking to break in. (Obviously, I am researching the basics on my own.)