Resistors do three jobs: they set currents, divide voltages, and pull signals to a known level when nothing else is driving them. Nearly every resistor you will ever place is doing one of those three things, and naming which one makes any schematic easier to read.
Values are not arbitrary
Resistors come in preferred values (the E12 series gives the familiar 1.0, 1.2, 1.5, 1.8, 2.2... sequence) because manufacturing tolerance made finer steps pointless historically. This is why you can never buy a 500 ohm resistor but 470 and 510 are everywhere. Designs should target a preferred value from the start.
The two ratings that matter
Resistance is only half the spec. Every resistor also has a power rating, and P = V x I decides whether a part survives. A 100 ohm resistor across 12V dissipates 1.44 watts and will cook a quarter-watt part in seconds. The habit: any time a resistor carries real current, compute the power before choosing the package.
Color bands are worth learning to read, but nobody is above just measuring: a multimeter on the resistance range is faster than squinting at whether a band is red or orange under bench lighting.