1. Shorten the string length: The shorter the string, the higher the frequency of the sound it will produce. This can be done by moving the bridge closer to the nut, or by using a shorter string.
2. Increase the string tension: The higher the tension of the string, the higher the frequency of the sound it will produce. This can be done by tightening the tuning peg, or by using a thicker string.
3. Change the material of the string: Different string materials have different densities and elasticities, which will affect the sound frequency. For example, a steel string will produce a higher frequency sound than a nylon string.
4. Use a thinner string: A thinner string will vibrate faster than a thicker string, producing a higher frequency sound.
By adjusting one or more of these factors, it is possible to increase the sound frequency of a particular string on a stringed musical instrument.