Once you learn more communes, such as Merauds, it becomes extremely easy to work Theurgy. It's one of the easier guild skills to use. All you'll ever need is Merauds, Eluned, and in occasion Tamsine.

It is very annoying at the beginning.
As soon as you get your hands on Tamsine's commune, do that as often as the timer allows.
Combine and use Eluned's Water commune with that (and the timer on this is shorter as well).

They don't hit your devotion very hard, so it isn't terrible to reclaim it. Pester every Cleric you see to teach Theurgy, some of us remember what it was like and don't mind spending some time making it easier for you.

At 20th circle you get Meraud's commune, which gives a massive amount of experience for a goodly hit to your devotion. At that point it is:
Eluned's Water commune, Tamsine's commune and Meraud's commune to mindlock, than let it drain and do it again. Strive to keep your devotion up in-between.

---

If you act like prey, do not blame me for acting like the predator I am.
DR_Shaidval @ AIM

Commune Meraud
Commune Eluned every 20 minutes
Commune Tamsine every 20 minutes
Pray god every 10 minutes
Pray dead creature every 10 minutes
Recite every 10 minutes

After a moment, you see a vision of your god who calls to you by name, "Come here, my child, and I will show you things of wonder." (13/16)

Theurgy: 1219 95% engaged (22/34)

I tend to use Sacrifice attacks fairly regularly to keep my devotion up. Only tricky bits are making sure you land a killing blow with it, otherwise it will give you a devotion hit. It also wont work on undead.

My method for it is simple enough: I just lay into whatever I'm hunting with my weapon until it starts taking heavy damage hits. Then I give it a quick app and move over to weaker attacks like feint and jab until I reach "extremely bad shape" or worse. Cast a quick soul sickness to immobilize it to reduce the chance of a miss, and finish it off with the Sacrifice. No timer on the devotion gain if you land a killing blow and it gives a fairly substantial bump. The messaging on it is fairly entertaining as well, but that of course is purely cosmetic.