To those that responded about priest/esses being in charge of serving their Gods, how would simply serving their Gods differ than say serving a laity?
For me, serving Brighid means doing the work She tells me to (whatever it is), keeping Her flame, and living the values She has set for me. It *might* involve "serving" other people in some way, but the *reason* is because it's Her work.
In contrast, pastors are responsible for ministering to their congregations, which can include everything from administrative and supervisory duties in the church to marriage counseling to preaching. My brother and SIL are both Methodist ministers, and I know they consider the service they provide to their congregations to be the work that God has set for them -- so, in that respect, they view their work for God in much the same way that I view my work for Brighid. But the nature of the work is different.
The work has been a variety of things over the course of my life, and I expect that variety to continue. F'ex, my training as a lawyer and work as a child and health advocate was Her work (although I didn't realize it when I started working on my masters or even my law degree). My work as a lighting designer is also for Her. My copious reading and studying about Celtic mythology, history, art, etc., was Her work. (That's in the past tense because my ability to read has diminsihed greatly as my health issues have gotten worse.) Being a foster mother for a while was also Her work. And, right now, focusing on my health and trying to heal is the work She has given me to do (a recent epiphany!).
Keeping Her flame is about several things: the offering of fire, itself; the work to help establish and maintain the Cill; the dedication of time during which I'm specifically mindful of Her and setting aside time for activities related to Her work. I consider the flame-keeping part of my responsibility to extend to all areas of my life. Although I have the 19th shift in the Cauldron Cill (and other shifts in a couple of other Cills), I am *always* a flame-keeper and I try to stay mindful of that at all times. One of my tattoos and a ring that I wear all the time are intended to help me with that.
The values are harder to define. Part of that is also about staying mindful of Brighid and always trying to understand what She wants me to do -- easier said than done!

Some of the values come from learning about Brighid, the role She plays/played in Celtic society, and Her areas of influence. Some come from learning about the values of Celtic society. And some come from my own UPG.
All that said, I should clarify that I'm not really comfortable with thinking of myself as a "priestess". However, if I'd lived in Bronze or Iron Age Ireland, I might have been a priestess of Brighid, if that opportunity was open to me. Since that isn't a possibility in my time and place, I think of myself as a "dedicant" of Brighid -- or something like that. However, regardless of what I call myself, in general, I see my responsibility as being first to Brighid and second to myself. That translates into some kinds of service to others. But I see clergy as being responsible first to their god and second to their congregation.
YMMV, of course.
