While you certainly don't care to track Power Word: Fortitude or Leader of the Pack, some useful things to check out are Inquisition, Zealotry, Avenging Wrath, Guardian of Ancient Kings, Golem's Strength (from Golemblood Potions), Divine Purpose, Divine Protection, The Art of War, and so on.
Personally, some of the main things I like to see are my Inquisition uptime around 90% or higher, optimal Guardian usage and proper Zealotry and AW stacking, and abundant Divine Protection usage.
Healing by spell
I know, I know -- we're not healers. We have healing spells, though, so if you're close to death you should be using at least one, right? Remember, you can't do much damage as a steaming carcass on the ground. Additionally, if you're pushing some progression content and your healers are still adapting to mechanics, covering some of your own heals and those of your fellow raiders could go a long way.
General trends are the most useful pieces of information you can be taking out of this section. Casting 15 Word of Glorys for a 5-minute fight could be a bit too much of a DPS loss in the long run, but strats and personal playstyles differ greatly. Some good things to check for are Healthstone usage, Sacred Shield procs, and Lay on Hands casts.
Of course, what log analysis would be complete without looking at your damage done? A lot can be surmised about the nature of the fight by the breakdown of your abilities, but you already know that stuff -- you were there!
Instinct will want to drive your attention to the Misses column, but that information is somewhat useless. If you parry a lot, that means you have been either standing in front of the boss too much (something you should be quite aware of) or you don't have enough expertise.
Similarly, if misses are tallying up, you simply don't have enough hit. Of course, there comes a point in the min-maxing number game where getting that extra 0.03% hit to reach the cap comes at a DPS loss through the reforging of other stats, and if you take this approach, you will naturally see a couple of misses here and there. Personally, I prefer to be as close to the cap as I can without going under, because if juggling those numbers means I miss a Crusader Strike, that tends to throw off my whole momentum. Granted, the impact is much less severe with two-piece T13, but it is still a morale-killer.
Another helpful tidbit is to compare your number of Exorcism casts (hits and crits, not ticks or tick crits) to the number of Art of War procs you gained by looking at the Buffs Gained tab. Again, hard-casting an Exorcism should be pretty obvious, but seeing how many Art of War procs you missed out on can be important.
If a fight involves killing multiple adds at once (Warmaster Blackhorn, for example), Censure can be among your top three damage sources for the encounter if you keep multiple stacks rolling on different targets. With the recent buff to Censure damage, this behavior has become all the more rewarding.
Last but certainly not least, we come to most informational section of World of Logs, the log browser. With this, you can browse your entire combat log and isolate things you would like to see. For example, you can see when all of your Divine Purpose procs occurred by setting yourself as the source and Divine Purpose as the spell, then running the query. Remember to remove the "Show all events" query first, as it just won't work without doing that!
Want to see if you spent that Divine Purpose on an Inquisition, Templar's Verdict, or Word of Glory? You can do that too (and in one easy step) by separating the spells with commas and running the query against the Divine Purpose query you just ran.
The log browser and its less user-friendly cousin, the expression editor, are great tools for evaluating just about anything you can think of in any given encounter. Learning to use these and other parts of World of Logs will help you become not only a better ret paladin but a more cognizant raider and a more passionate player as well.
The Light and How to Swing It teaches you the ins and outs of retribution paladins, from Ret 101 and how to gem, enchant and reforge your retadin, to essential ret pally addons.