For example, I am looking for the full Devil May Cry 4 soundtrack. The one that isn't hosted on Rapidshare. But I type it in the search engine (specifying only the request/downloads forums) and I get a ton of hits back for download links for the other games in the series.

Is there anything I can do to increase the efficiency of my searches? For example, how would you search for "Final Fantasy X Unreleased Tracks?"

Apart from only searching topic titles or asking for it. I don't think you can.

http://forums.ffshrine.org/showpost.php?p=1064694&postcount=2079
It's just a matter of patience when searching, it took me 3mins to find that and what i did was typed in unreleased tracks, saw the final fantasy thread, saw the links on the first page were dead so i searched the thread using search this thread and found it easy enough.