Christine, I'm in charge of picking the featured articles. I have a master list of 500 members, and I'm working my way through it alphabetically (by first names), picking 4 or 5 writers every month (depending how many Mondays are in the month).
Right now I'm in the S's, I think, so it'll be a while before I get around to the C's. I used to pick the featured writers more randomly, but I found that I'd gravitate toward names that I recognized, and I wanted to be sure to feature 500 members who weren't necessarily active on the boards or the Writing Challenge in addition to the more familiar names.
I look both at Challenge articles and Regular Submissions, and I try to get pieces that are free from errors, unique, and especially with a great hook, as the first 150 words or so are posted on the front page, with a link to the entire article. So your best chance of getting picked is to be sure that you have a number of pieces that won't require editing before being featured. A great title is an asset, too--something that'll catch my eye as I'm looking through the hundreds of possible stories/articles/poems.