The important thing to consider about the base of your capo is that it is long enough to cover the width of the fretboard. If you have a short pencil or another shorter base, test it by comparing its length to the width of the fretboard. [1] X Research source

If you use an elastic band, test it to make sure it is strong enough to hold the base against the strings. Test the elastic band by stretching the band. You don’t need to stretch it too far, but make sure it doesn’t break on an initial test. [2] X Research source

Loop the other end of the elastic band or string around your base. Detach the loop before attaching to the guitar.

Depending on what elastic band you use, you might need to double loop it to increase the pressure. The pressure needs to be high to effectively press down the strings across the fret. [4] X Research source

When you test the capo, play chords in the open position to test if the open strings sound good. The open strings are the notes that are affected by the capo. [5] X Research source