THATS A GREAT QUESTION
I've never figured this out. It seems like there's a very basic metric (titles are listed higher than tags, for instance), but after that the order doesn't seem to change based on any relevant metric -- I remember looking for any explanation for why certain titles were listed ahead of mine, and I couldn't find anything at the time. The order doesn't seem to move, either -- so like, if there's 30 titles ahead of you, there will always be 30 titles ahead of you (unless a new comic joins that gets added higher in the list, in which case there will be 31).
Anyway yeah, I added some tags to my comic that I felt would be worth searching, just in case, but the search results aren't really a very useful way to find new comics.