In Classical guitar playing there are two basic methods of picking the strings with the right hand – rest stroke and free stroke. The first method you will learn is the rest stroke.
Rest stroke is performed by plucking a note with your finger and then coming to rest on the next lowest string, as shown in the photos. To keep your hand balanced when playing a rest stroke, rest your thumb lightly on one of the bass strings.
With your thumb resting correctly, place your i finger on string one (E string).
Pull the finger across, using the nail and let it come to rest on the second string.
Now bring your m finger to the E string and pull it across to the second string, at the same time bringing the i finger back to the first string. This alternation can be done with any of the right hand fingers: m-a, i-m or i-a. Do not use the very middle point of the nail, but strike the string more to the left of the nail. This means that you will have to slightly turn the fingers and hand in towards the sound hole.
This example demonstrates four bars of quarter notes played on the 1st string (an E note). Alternate the i and m fingers as indicated above the notes. Remember to rest your thumb on a bass string to keep your hand in the correct position.
Now try playing rest stroke on the open 2nd string (a B note). Be sure to alternate the i and m fingers.
For this example, use the m-a combination on the G open string, as indicated above the notes. Then go back to the open E and B strings and use m-a on those as well.
Once you are comfortable walking the fingers on a single string, try crossing between strings as shown here. Play slowly and evenly and be sure to use strict alternation of the fingers. Once you can play this example using i and m, try using m and a.