2. Find the wobble
Hold a cable tie on the frame so its end almost touches the rim. Spin the wheel slowly and mark with tape where the rim touches it. That is the part to pull back.
3. Small turns
Spokes pull the rim toward the side of the hub they come from. To move the rim away from the tie, tighten the spoke on the other side by a quarter turn and loosen its two neighbours by an eighth. Spin, check, repeat.
4. Even tension
Squeeze pairs of spokes all around the wheel: they should feel about the same. A spoke much looser than the others will let the wheel go out of true again soon.
5. Settle the wheel
Press firmly on the rim all around, on both sides, to settle the spokes. Check once more. If a wheel needs more than a few turns, or a spoke breaks, bring it to the workshop.