Important in tonal musical composition is the scale for the notes used, including the mode and tonic note. In music using twelve tone techniques, the tone row is even more comprehensive a factor than a scale. Similarly, music of the Middle East employs compositions that are rigidly based on a specific mode (such as the dorian, phrygian, mixolydian, and locrian scales), often within improvisational contexts, as does Indian classical music in both the Hindustani and the Carnatic systems, gamelans of Java and Bali, and much music in Africa.
People who practice composition are called composers. Compositional techniques are the methods used to create music. Useful skills in composition include writing musical notation, instrumentation, and handling musical ensembles (orchestration). Other skills include extended techniques such as improvisation, musical montage, preparing instruments, using non-traditional instruments, and other methods of sound production.
Based on such factors, composers or arrangers must decide upon the instrumentation of the original work. Today, the contemporary composer can virtually write for almost any combination of instruments. Some common group settings include music for Full Orchestra (consisting of just about every instrument group), Wind Ensemble (or Concert Band, which consists of larger sections and greater diversity of wind, brass and percussion instruments than are usually found in the orchestra), or a chamber group (often ca instrumentation of at least two instruments). The composer may also choose to write for only one instrument, in which case this is called a solo.
Composers are not limited to writing only for instruments, they may also decide to write for voice (including choral works, operas, and musicals) or percussion instruments or electronic instruments. Alternatively, as is the case with musique concrète, the composer can work with many sounds often not associated with the creation of music, such as typewriters, sirens, and so forth.
In Elizabeth Swados' Listening Out Loud, she explains how a composer must know the full capabilities of each instrument and how they must complement each other, not compete. She gives an example of how in an earlier composition of hers, she had the tuba above the piccolo. This would clearly drown the piccolo out, thus giving it no purpose in the composition. Each instrument chosen to be in a piece must have a reason for being there that adds to what the composer is trying to convey within the work
In the UK, "music" is normally understood by law to include melody, harmony and rhythm.