Never eaten a girl out and desperately need to learn

Okay so I'm a guy, but who knows best how to eat woman out if not woman? My current dilemma is that I'm in this relationship of sorts and I know that oral is going to come into play sometime soon. Oral is pretty much the Isle thing I've never done aside from anal and I'm pretty clueless. I want to do a good job, even though I know it's pretty impossible to be great the first time, I'd like to Atleast be good. Any and and all advice would be really really helpful!