I tuned in here because I, too, am completely clueless as to how to use a GPS. After three years, I'm still struggling with the owner's manual of my digital camera, so I suspect there's not much hope for me!
I have, however, had 68 years' experience with map and compass and have learned a lot of "seat of the pants" navigation as well--finding traces of abandoned trails and "reading" the terrain to determine where they might go next. None of these priceless experiences (thanks to my long-departed parents!) can be compensated for by a GPS, IMHO. Supplemented, yes, but you need to develop manual skills first.
This brings me to Tango61's point about turning around to check your back trail frequently. I can't stress sufficiently the importance of this! I do it even on trails, especially at trail junctions. It's amazing how different a trail can look when you're going the other direction! This fact is, after all, the saving grace of out-and-back hikes--you always see a lot of new things on your way back!
Here's a site I just found that will give you some basic info on map and compass skills. (The one I used to recommend seems to have disappeared from the internet, but this one looks good.)
There are orienteering clubs all over who make a competition out of map-and-compass navigation. This looks like a fun way to learn navigation skills!