==== Batteries ====
The first option is to use priest "batteries". These are priests that typically only have high levels of faith allowing them to hold large amounts of favor. If you link these batteries to your primary casting priest then you can draw on the favor of the primary priest and any linked batteries when casting. You may add one linked priest for every 10 levels of channeling ability. Linking priests seems to increase the level of difficulty when casting. I have not yet been able to verify that this is indeed the case although it is very commonly mentioned and there is the feeling that this is the casetrue.
When using linked priests you can often just click the casting button from time to time after favor has regenerated enough to do so. The number of linked priests directly impacts how often you can click that button. Six linked priests make it very possible to skip sacrificing items entirely for favor gain without having to wait an extremely long time between casting attempts.