How to Balance a Paper Airplane

Before changing trim, compare both wings. Uneven wings cause turns that look like balance problems but are really asymmetry.

Tiny upward bends at the back of the wings (elevators) help a diving plane. Tiny downward bends help a plane that climbs and stalls.

Change both wings the same amount unless you are intentionally creating a turn.

A small piece of tape near the nose is a reversible ballast test. The Experimental Glider page is built for this kind of methodical change.