Aural Skills
Aural skills training is an important part of developing your musicianship. All contemporary musicians learn cover songs as part of their repertoire. Being able to recognise chords and intervals and scales & rhythmic patterns is essential to being able to work out songs by ear. You may already be doing this, but developing your ear will make you more accurate and faster in doing so.
Singers should be able to identify intervals and scales so as to quickly and more accurately learn melodies in songs. Being able to identify intervals and scales helps singers to better their improvisational skills.