Priest
Those dedicated to a god might not all be wielding powerful divine magic, but they full an important role in bringing their god's desires to the world. Most of them are carefully guiding those around them, overlooking a community and possibly recruiting to the cause, but what that means depend a lot on the god in question...
Career
Qualifications
Any priest must both be a good ambassador for their god, a shepherd for those who follow them, and a representative for what the god stands for. All of Moradin's priests know the basics of working with stone or metal. Kelemvor's priests will help guide others in how to deal with death. Oghma will want his priests to go spread knowledge where they can.
Career Progression
Any church, cult, or order will have some sort of hierarchy. Some even proclaim that there are places next to the deity they worship. Devil-worshipping cults are very fond of claiming that one can become a powerful devil, for example...
Other Benefits
The financial rewards of priesthood are often not that much (unless you serve Waukeen), but they often become very trusted members of the community and someone others will turn to for advice. Not to mention, having a god on your side can be rather helpful.
Operations
Workplace
Not all priests work in temples and not all temples are traditional stone structures. Temples to Maliki are often just a clearing in the forest and temples to Cyric are usually hidden underneath other buildings.
Provided Services
Everything from naming ceremonies, to coming of age rites, to weddings, to funerals - all of it are things that priests might be called on to do. And those are only the big events. For the most part, they are there for constant advice to those who need it, providing information to those who should have it, and making sure their patron diety is given what's theirs.
