Check that the wheel is fully seated in the dropouts or axle
Loosen the caliper mounting bolts slightly
Squeeze the brake lever firmly to center the caliper on the rotor
While holding the lever, tighten the caliper mounting bolts
Spin the wheel to check for rotor rub
If the rotor rubs, slightly loosen the caliper bolts and realign the caliper
If the rotor is bent, straighten it with a rotor truing tool
Adjust pad clearance if your caliper has a pad adjustment dial or screw
For mechanical disc brakes, tighten or loosen the cable tension barrel adjuster
For mechanical disc brakes, loosen the cable pinch bolt and reset cable tension if needed
For hydraulic disc brakes, pump the lever if it feels spongy
For hydraulic disc brakes, check brake pad wear and replace worn pads
For hydraulic disc brakes, check fluid level and bleed the brakes if necessary
Test the brake lever feel and stopping power
Recheck all bolts after adjustment