Way back when there was no GPS, I learned navigation with map and compass. Still use it, as I don't always trust a GPS - shades of Mayhem and recalibrating.
The key is terrain association. If you can read the map and know what it is showing and can translate that to the ground, you are good to go.
Triagulation (I learned it as resection) isn't hard, just tedious finding two known points and a place high enough to take readings from. Still, if you can do terrain association you shouldn't have to do it too often.
And then the golden rule, if you haven't found your objective, you are more than likely short, not long.