Books

DK: Help Your Kids with Music
Great starter book for novices on everything from notation, pitch, rhythm, intervals, melody, and harmony to form, styles, voicing, and more. Easy to use solo or with a teacher.

Music for Sight Singing
Robert Ottman's famous introduction to rhythm training, conducting, sight singing. Lots of graduated practice material. Older used editions are just as good and less expensive.

Rhythmic Training
Starer's book offers practice with more complex meters, divisions, and polyrhythms for students with basic knowledge of rhythm and notation. A classic resource.

Modus Novus
Lars Edlund's famous (infamous?) work for students of atonal sight singing and ear training. A much feared little book. Challenging, to say the least.

Alfred's Essentials of Music Theory
Introduction to music theory and ear training for beginners. Book and two CD's. Yet another classic music program resource.

Bach Riemenschneider
371 Bach Chorales and 69 Chorale melodies with figured bass. Enough material to keep hard working music students productively engaged for years. Free pdf here.


Gear

Midiplus AKM322 MIDI Keyboard Controller
Midi controller fits in a suitcase. 32 velocity-sensitive keys, piano-like feel, DAW, arpeggiator, pitch/mod, octave/transpose. Every music student needs a small keyboard like this one.

KLIQ MetroPitch
Three-in-one device: visual and audio metronome (multiple beats and rhythm patterns), tone generator, and instrument tuner.

Little Martin Guitar
3/4 size, big Martin sound, great playability, and easily portable. Excellent for small hands, travelers, beginners, and pros alike. Competing Baby Taylor guitar here.


Other

Rick Beato
Amazing musician and music teacher. Awesome
instructional materials. Fantastic YouTube channel. If you're serious about popular music and music study, check him out.

Reddit Music Theory Forum
Wide-ranging reddit forum. Discussion threads cover just about all aspects of music theory and composition. Useful list of best theory apps and books here.

Best Ear Training
Music teaching site timtopham.com provides recommendations for aural training apps. More recommendations here. Beato course here.

MuseScore
Free, open source music notation software makes composing and publishing beautiful music almost easy. See: Mastering MuseScore and Mastering MuseScore Online.

Tabulature
Musical notation for fretted instruments indicating fingering rather than pitch. Common centuries ago, it's making a comeback with guitar/bass tabs. Additional info here and here.