Music books can be a great resource for beginning and advanced students alike!
Many teachers recommend purchasing lesson books that develop in levels. The Faber Piano Adventures series is incredibly popular. The series is written in levels, from pre-music reading all the way up to relatively advanced pieces. Using series lesson and performance books allow students and families to see what they will be learning and how far they have come.
Music anthologies hold many songs usually by either the same composer or in the same genre. Learning from these anthologies can help students stay organized by having all of their music in one place.
Sheet Music or Tabs
Many teachers prefer to work with individual songs notated as sheet music or guitar tab sheets. Using single songs allows students to choose from a wide variety of composers and genres.