One of the most often played and recorded pieces of classical guitar music must surely be Franisco Tarrega's Recuerdos del la Alhambra which translated means "Memories of the Alhambra" - Alhambra referring to the beautiful Moorish Palace in Granada. I have even heard it being referred to as "The Guitarists' National Anthem'!
Mastering the all important tremolo technique that this piece demands for a successful performance is no mean feat and can take years to perfect. I was a late starter learning tremolo and it took me a good 5 years at least before I felt comfortable with the technique. I'm sure it is different for other players and perhaps it comes more quickly for those who start at an early age.
Here is a recording of this famous Tarrega piece which I was privileged to be allowed to perform one evening in the magnificent entrance foyer of the Auckland War Memorial Museum.