To be honest for me it was mostly trial and error . . . that and asking lots of questions about geocaching.
I remember when I first started and I didn't realize you could punch in a waypoint with the coords . . . instead I would look at the coord screen and walk forwards, backwards or sidewards in an effort to get the numbers to match up to the waypoint listed at geocaching.com. Of course I have a Magellan (actually two) GPSr so now I still do the "dance of the geocachers" even with the plugged in coords.
As I said, for me it was simply going out and learning as I went . . . started out with easy rated caches and then progressed to the more difficult caches. I didn't set out my own cache until I had found something like 25 or 50 . . . by then I knew what I did and didn't want to do with my own cache.
As I progressed I learned to come here or the forums at gc.com and ask questions . . . or you could go to an event and ask questions. The key thing is to ask questions.
The nice thing is that the County has several active geocachers and there are some great caches up there . . . one of my all-time favorite caches was one I found at Loring at the site of the old Phish concert.