We all have realized that Book 1 of The Legend of Korra was shorter than the books of The Last Airbender. This is since the series was intended to be a miniseries, meaning there would be no filler. So, if the series wasn't intended to be a miniseries, there probably would have been 8 episodes of filler (or a few filler episodes and more plot episodes).
But anyway, on to the point of this blog. Write or just summarize your idea for a filler episode from Book 1: Air.