I have 26 editor's choice out of 154 hubs. I don't think there is any trick to getting them. If the hub meets all the criteria to be featured (proper spelling, grammar, length and picture usage) then it's eligible. I assume they're awarded based on traffic and niche. If you're the only one who wrote an article about fishing in Colorado, then they want your hub to be featured in the Colorado fishing category. I don't think such a category exists, but you get the idea. They want quality hubs representing each section of the site. If that section is crowded, there is less chance you'll get the editor's choice.