Understand that you true a wheel by tightening and loosening spokes. You can true a wheel both laterally and radially.
Assemble the proper tools. You will need a truing stand, a spoke wrench, and some light oil.
Remove the tire to true the wheel laterally.
Set your wheel in the truing stand.
Set the truing stand with the arms close to the rim. Dial them in so that the side of the rim scrapes in places.
Place one drop of light oil where each spoke threads into the nipple, and another drop where each nipple sits against the rim.
Relieve stress on the spokes by squeezing sets of parallel spokes with your hands. Go through the whole wheel before you begin truing.
True the wheel laterally by tightening the two spokes that pull the rim in the opposite direction from where it scrapes, and loosening the one spoke between those two spokes.
Tighten a spoke by turning the spoke wrench counter-clockwise. Loosen a spoke by turning it clockwise.
Turn the spokes a quarter turn at a time.
Set the truing stand so that the arms are underneath the rim and scrape the top of the rim in various places. To true the wheel laterally, tighten four or six spokes along the area where the rim scrapes. When you true a wheel laterally, always work in pairs of spokes - one spoke from each side of the hub.