You should have a few ranks of consecrate bound as well besides just max rank. You want to tailor your consecrate rank to the duration of the fight and your mana. When you don't have the mana for a full rank consecrate you can still drop a lower rank to have some extra dps, and when you can you drop higher ranks as mana allows. Any mana you end the fight with is sort of wasted dps which you could have been dumping into consecrate.
Keep it up with the ret though, it's a very fun spec to play.
