You don't really have any control over that, as its specific to the buyer doing the searching.
From eBay:
"How "Best Match" Sorting Works
"Best Match" lets you sort the listings you see based on a concept called relevance. A particular listing's relevance is based on past buyer behavior, as well as information like the listing title and description.
With Best Match, what buyers do on the site affects the order in which listings are displayed. In other words, if buyers running a particular search often end up viewing, bidding on, or buying, a certain type of item more often, this will be factored into our relevance calculations. These types of items might then display higher on the page in subsequent searches.
One very important note: using the Best Match sorting option won’t change which items you see when you search – only the order in which listings are displayed."
It looks like they have recently taken into account the sellers performance as well for determining the 'best match' for buyers. This means sellers with bad feedback scores, or who charge much higher shipping rates than others will appear lower on the list.
Note however that many buyers on the eBay forums dislike this new sorting option and still re-sort their results based on ending soonest timeframes.
Regards,
Christopher
[ edited by ChristopherCS on Mar 11, 2008 02:44 PM ]