Master the art of arranging music for multiple instruments—transforming piano sketches or melodies into rich, full-ensemble pieces. Study instrument ranges, timbres, and capabilities (what each plays well). Learn orchestral families: strings (warm, sustained), woodwinds (agile, colorful), brass (powerful, heroic), percussion (rhythmic, punctuation).
Understand doubling (reinforcing lines), countermelodies, texture (thick vs. transparent), and balance. Study scores from great orchestrators (Ravel, Rimsky-Korsakov, John Williams). Use software like MuseScore or Sibelius to hear arrangements. Orchestration teaches you to think in colors and layers. Applicable to film scoring, game music, concert works.
Each instrument has personality—orchestration is casting the right voice for each musical role.