Inspired by BrianM's
Brick bumping, in which he could only find the crappy thread for that movie. There was a better one in existence, but it wasn't revealing itself easily through the normal means.
There's already an entry on this list about using google, and it's very very great. Almost everything can be found through the ol "[search terms]
site:chud.com/forum" method. But some things can't, and sometimes there's an even easier way:
37. Pay attention to the "Similar Threads" section at the bottom of the page.
If you find one thread on a topic, but you know there's a better one, scroll down and chances are the link awaits you.