eBay recently changed its default for results on Best Match. 80% of buyers NEVER change how search results are displayed. You want to be at the top of these search results to catch the "lazy" buyers who aren't going to change the search result order, and get the clicks.
Watch this 10-minute video about how to optimize your listing in eBay's Best Match Results. A summary:
1) Your listing's title is much more important than ever - certain words result in more clicks.
2) Learn how to use eBay Research Labs (FREE) to optimize key words in your title and strategically use all 55 characters in your item title.
3) Learn how to determine what words "buyers like" when they search for a particular product.
This video is well worth watching, and only takes 10 minutes.