Astronomers before GPS found their way with a trick you can learn in one evening: use the stars you know as signposts to the ones you don't. Add the brightness scale and one planet-spotting rule, and the sky becomes a map.
Signposts, not searching
The sky is too big to search, so nobody searches — they hop. The Big Dipper is the master signpost of the northern sky: follow the two stars at the end of its bowl and they point almost exactly to Polaris, the North Star, which sits within a degree of the sky's rotation axis — the one star that never moves all night. Follow the arc of the Dipper's handle instead and you 'arc to Arcturus', the brightest star of spring, then 'spike to Spica' beyond it. Every constellation you learn becomes a signpost to two more; the sky is a network, and you only need one entry point.
The upside-down brightness scale
Star charts label brightness in magnitudes, and the scale takes one minute to decode: it runs backwards (smaller numbers mean brighter), it's ancient (the Greeks called the brightest stars 'first magnitude'), and it's logarithmic — a difference of 5 magnitudes is exactly 100 times in brightness. Your naked eye reaches about magnitude 6 under dark skies; city glow steals everything past 3 or 4. That one number explains most disappointment in stargazing: a 'bright' galaxy at magnitude 8 is invisible without help not because it's small, but because your pupil is a 7-millimeter bucket — which is exactly where the telescope lesson picks up.
Planets break the rules — usefully
Two rules unmask planets among the stars. First: stars twinkle, planets mostly don't — a star is a point of light shredded by our turbulent air, while a planet is a tiny disk whose shimmer averages out into a steady glow. Second: planets only ever appear along the ecliptic — the same highway across the sky that the Sun and Moon travel, because the whole Solar System is a flat disk seen edge-on. A brilliant, steady, untwinkling light on that highway is a planet, almost every time. That's the whole secret behind friends who point and say 'that's Jupiter' — they're reading lanes, not memorizing dots.