As a warlock, my combat log was always a mess to sort through. I would have to search between the ticks of every DoT that I had cast in order to find the information on other specific spells that I was looking for. As you can imagine, it was a tedious task, especially for long boss fights, where I could potentially lose a portion of the encounter due to the volume of DoT data pushing the rest out of the window. Fortunately, I came upon a pretty easy solution to this problem.
I created a new window and named it "Dots," and configured it to only log periodic damage data cast on enemy targets. I then removed this selection from my combat log. The result are two separate logs, one which deals with direct, burst damage, and the other that deals with periodic, DoT spells. All of the original data is retained, but now, it's just much easier for me to sort through -- kinda nice.
I went a step further and created a dedicated window for whispers and officer chat as well. This way, personal messages and officer-related information don't get lost in the crit-worthy general, trade, and sometimes guild-centered walls of text. The information is saved in a different window, and therefore is available to me for a longer period of time.
This simple yet effective tweak to my windows helped me to get much more organized with the constant flow of data we receive. There's lots of possible applications, so mess around with it a little and let me know if you come up with anything useful. =)