Written instructions are easier to follow when accompanied by pictures. If you can't draw, see if you can talk an artist friend into helping you out. Documentation is good. Demonstrate the relationship between your work and a medieval subject or activity. If you submit a poem, include two or three paragraphs on how the form or subject matter conforms to a period model.
Passion is good.
Draw or write about something you love. It will come through in the final product. All articles should be typed and double-spaced. If at all possible, please include an electronic copy of your article with your submission. Most MS-DOS, Windows, and Macintosh formats are acceptable, provided you label the diskette appropriately.