Turn the tuning knob in a clock-wise motion to tighten the string until the string makes a clear sound when plucked.

As you tighten the string, be sure to hold the string with your free hand until the string stays tight on its own. This will keep the knot from loosening.

As the string winds around the tuning peg, make sure that the string passes over the loose end from the knot at least once. This will prevent "slipping" (detuning) during tuning and will help keep the knot tight.