When you're fighting the humanoid, avoid judging him when at all when he's under 30%-40%. You should have enough of a threat lead at this point that the DPS can burn him down while you hold aggro with Consecrate/Holy Shield/SoR. As long as the DPS isn't slow as molasses, I tend to completely ignore the humanoid at ~25% and prepare for the dragon.
Typically, when I did it at 60-62 as a non-heroic, soon as the dragon landed I would whack him with a JoC for the extra holy damage and then an Avengers Shield. Immediately bring up SoR and then HS/consecrate and fall into your normal rotation.
Also remember the 'basics'.
-Righteous Fury (duh

)
-use FR aura (helps reduce the party damage, this fight often surprises most new healers)
-try BoPing the healer (typically who the dragon will go to when he lands) 2-3 seconds before the dragon lands
-Salv all the DPS. I get complaints, but whenever I pug the DPS gets salv or I don't tank, it's that simple. You're not facing enrage timers, so I would prefer to take a few more seconds by using Salv over DPS blessings and risk someone pulling aggro.