How to teach beginner composing
From the very beginning of learning finger numbers, to complicated chord progressions, some piano students will excel in composition. Some people are just more right brained and creative types. All students, however, can be encouraged to compose. Those who would be less gifted at composing would probably compose underneath or at their current reading level. Those who are gifted at composing will probably compose things that are too difficult to play, and thus need to practice it! This process will naturally lift them to a higher plane of playing, by making their own music. The following is an example of how things could be taught, and must be used to individual adaptation when necessary. Everything you, the teacher, have learned from music theory, will be applied as you move forward in composing.
These types of students will just naturally respond to your invitation to make something up. These students tend to be the ones that have definite opinions as to what they want to make up. Usually students who aren't as compositionally oriented are ones that don't want to take a guess as to what to make up. Encouraging all students to just guess and check at their notes is a good way to teach them that they can do it. Because at the beginning stages, there are very few wrong answers. Only when harmonization is taught, is there bad sounds to be had.
Composing for young ages
For the the younger ages (around 6), when the musical alphabet is not understood, floating
quarter notes can be written out in 4/4 time right in their student assignment journal (say, 4 measures of quarter notes), a hand position can be agreed upon (either on white or black keys), and the student can be asked to provide finger numbers for their composition, the piano teacher writing them in. Advise them only to use the notes you assign in their position.
Working closely with the mother/father that is in the lesson will allow for practice of this composition over the week. Depending on the situation, you could leave some quarter notes blank, and have the student and parent work on it together. Suggest that they can change any notes they want at any time. An example could be to have 2 or 4 measures of quarter notes for the right hand to fill in, and 2 or 4 measures of quarter notes for the left hand.
Rhythm is a difficult concept, and could be introduced slowly as an idea in to composing. As the piano teacher, you could write out different rhythms, asking them to fill the finger numbers in that they desire, according to their current rhythm knowledge. They would have to count and play eventually as well of course.
Eventually, the musical alphabet can be introduced, in which the student would then write in which actual notes they desire. At this point a middle C position (both thumbs sharing middle C) can be adopted if it hasn't yet. And eventually a C Major position can be used (RH CDEFG, LH CDEFG). Also at this point, or the moment that the white keys are used, a rule can be introduced: they must start and end their song on C ( in order to teach resolution and the first concepts of the tonal 'home base'). If they are still using finger numbers but are on the white keys, teach them to start and end on the 1 finger.
Once in the C major position, the idea of question and answer can be explained too: have 4 measures of the RH and 4 of the LH be composed. The first note of the RH starting on C (or the 1 finger), the last note of the RH ending on G, or the 5 finger. The first note of the LH (which would be the 5th measure of the piece) would start to answer the question by starting on G, or the 1st finger, and the last note of the LH (end of the song) would end on C, or the 5th finger. Thus, the first elements of form are introduced.
Introducing Rhythm and dynamics at the right time will add to the options the student has to compose with, but should never be too complicated to make the song too difficult to write.
More and more, the student would be expected to become independant, writing more of the composition at home, and less in the actual piano lesson.
The introduction of harmonization
Eventually, the concept of playing 2 hands at the same time can be introduced. Start by having them compose a song like normal, floating quarter notes in the air, and putting in the chosen musical alphabet letters under the notes in a C Major 5 finger hand position (CDEFG) for the right hand only (maybe 4 measures). Then with the left hand in a C Major position on octave lower, have them chose whole notes for each measure that would play alongside the right hand notes. Explain that they are allowed to use only whole notes in the left hand, and that they can chose to use either C or G only (obviously mimicking the I and V chords). Have them play through each measure and choose which note (C or G) to play in the left hand. Again, a student naturally gifted at composing, will usually choose the correct note that harmonizes the best with the right hand. If their right hand mostly focuses on the notes that outline the G7 chord, it will be obvious that a G in the left hand would be appropriate.
At this point the RH should be the only melody. It would be the question and the answer in the melody. But this is negotiable.
If their melody mostly focuses around the C Chord, then C in the left hand will be chosen. If they chose the obvious wrong answer, play each choice back to them and see which one they like more. Ultimately, the choice is up to them, and there is definitely gray area here.
Have them practice their new song. Don't be surprised if it is difficult to play! Especially if they haven't began practicing hands together in their lesson book yet.
Eventually, F in the LH can be introduced (suggesting the sound of the IV chord), and now they have 3 options. Once this is mastered, all of these options can be replaced with the actual chords. The C chord being in root position, the F Chord in 2nd inversion, and the G chord (Or G7!) in 1st inversion. At this point, instruct them to start and end on the C chord, as well as possibly using the G chord as the 'question'.
They will need a few weeks sometimes just to master the chords, and this must be a separate endeavor. Writing down the notes for each chord and the fingering involved for the LH is important. Then they can choose which chord to place where, just like they chose C, F, and G. At this point, the chords could be just placed over the RH notes that are written down, as chord symbols, rather than writing out the chords below the write hand. This could be the beginning of teaching chord symbols.
If desired, these processes could continue in different keys as well! Teaching them the same chords but for neighboring keys like G Major, F Major, D Major, E Major, etc. They could even learn to transpose their song into a different key.
If you, the teacher, at this point, has never tried composing before, this is the time to try! Play around with the C Major position, creating your own song with a total of 8 measures, starting and ending on C, the last note of the 4th measure in the RH ending on G to form a question, then the next measure answering by starting on G and ending on C at the end of the song. Play the 3 chords in the LH harmonizing correctly with the RH, starting and ending on the C chord.
Your assignment is to record yourself audio or video, playing a song you made up between 30 seconds and a minute long.
This has been an introduction in teaching beginning composing.