When it comes to the right hand, developing a good technique by practising fingerpicking exercises on a daily basis, will help tremendously.
Of course for folk guitar, most fingerpicking is done using the thumb, index and middle fingers, but some folk guitar patterns and certainly classical guitar fingerstyle also uses the ring finger.
It is a fact that if you develop the weaker fingers on your hands, it helps the control and the development of the stronger fingers. If classical players practise exercises using their pinky finger to improve the control of their ring finger, it is a good idea for folk guitarists to practise using their ring finger to develop the middle finger and so on.
A daily exercise for the fingerpicking hand could include as many pattern combinations as possible also including an alternating thumb bass.
Taking it to the next stage might include hammer-ons and pull-offs, also known as slurs. Combining left hand exercises at the same time will obviously be twice as efficient in using your time.
