Perhaps I should have entitled this "My Threat Cycle" as this post will only cover what I do to generate threat.
Many of my tools are situational, so each situation is a little different. First you have to think about the basic questions that come up every time you endeavor to top the threat table.
Which Seal? Which Judgement? What Rank of Consecrate?
An as Alliance Paladin, I have two seals to choose from: Seal of Vengeance and Seal of Righteousness.
My preference is going to be Seal of Vengeance, but I have to examine the dynamics of the fight and think about how easy it will be to maintain stacks. If the fight is fairly stationary, and doesn't involve any prolonged time away from the boss, I want to be building and Judging full Seal of Vengeance stacks. Over time, Seal of Vengeance will do more Threat than Seal of Righteousness.
Seal of Righteousness is a better Seal when you need to burst your TPS (generally at the beginning of a fight). With my spell damage (around 300-350 buffed), it takes a 3 stack of Vengeance to get a bigger Judgement than a Judgement of Righteousness. Righteousness is my Seal of choice for all trash fights, and the early part of all Boss fights. It's also the Seal I want up on transition phases that wipe DoTs.
As to what Rank of Consecrate to use, I generally use Max Rank. Instead of having all those ranks on my hotbar, I just have 1 button that gives me two different ranks. Rank 1 if I Control Click it and max rank for a normal click. If I'm running a bit low on Mana, I will just not use Consecrate as it requires a good bit of mana each cast. Consecrate is usually my #1 threat ability in terms of TPS.
There is also the question of which Debuff Judgement I want up on the mob. There are the times I really wish I had Sevenn, our resident Retribution Paladin. With Crusader Strike, he can keep all the Judgement debuffs up at once.
When thinking about Judgements, I just look at what I need most for that fight. Do I need more mana (Judge Wisdom), or Threat (Judge Crusader) or Healing (Judge Light).
As to the cycle of abilities themselves it usually goes like this:
Open with Avenger's Shield.
Activate Holy Shield.
Judge Righteousness. Reseal.
Judge Righteousness again. Reseal.
Keep HS and Consecrate going.
When the Judgement timer is up, Seal up the Debuff I want, and Judge. Reseal Vengeance (or Righteousness)
Alternate Holy Shield refresh, Judging/Resealing, and Consecrate.
For Mag specifically, I was able to go with Seal of Vengeance, and I choose to Judge Light on him, as I always had plenty of mana from his incoming damage and I thought it would help ease the load a bit on our healers.