Start With Numbers, Then Read Music
The best starting strategy at the piano is to start kids with numbers (or a similar, soft approach) and then later read music. Reading music is really quite difficult and unenjoyable for most kids, in the early stages. This leads to a huge level of frustration that must be dealt with by the teacher.
Most kids struggle with the uninteresting pieces of beginning piano, become disillusioned, and finally quit when they realize that Jingle Bells is all they will ever play. If you only read music, your musical diet is limited to whatever your reading skills allow. With most kids, that is a very stark and discouraging diet.
Piano Is Easy
Play Fun Music Without Reading
What Piano By Number does is allow the child to have simple, childish fun with the piano, making music, before they start to try reading music. With Piano By Number, even quite difficult pieces, like the Moonlight Sonata or Fur Elise, are made easy for kids to play, and this fun leads to enthusiasm.
Any song can be translated into numbers, making it accessible to every child. It's very difficult to interest a child in an instrument with which they have nothing but difficulty, and most piano teachers ignore this fact as the child fumbles through piece after piece.
Even Simple Songs Are Hard To Read
The simplest song, presented in conventional notation, can pose a myriad of problems for beginners.
Let's use Mary Had A Little Lamb as an example.
Children will be confused by the "circles" (the notes) and will want to know why some are hollow and some filled in solid black. They will want to know what the "rest" (the little rectangle) at the end of the song means. And we've left out many common notation symbols in the interest of clarity.
The result is a child mired in the minutiae of notation, and that is not even counting the struggle they will have translating those "notes" on the page into corresponding "keys" on the piano.
The Areas Of Confusion
There are usually three areas of confusion: on the page, on the keys and in the combination of the first two. As soon as the child encounters these intellectual difficulties, they may decide it is too hard for them. Kids are very aware of their capabilities, even if some are more adventurous than others. If a child believes that something is too difficult, the teacher's task becomes infinitely harder.
Below is Mary Had A Little Lamb in number format, with a numbered piano keyboard below:
Numbers Have Less Dimensions
Numbers have really only two dimensions, up and down. Even very young children understand this. The multiple dimensions of musical notation are a huge stumbling block, even for older kids. Numbers are immediately transparent to kids, and they start making music right away. Reading music comes a little later.
Having gotten the child to see that music is fun, it is then much easier to introduce more difficult elements, at the child's pace. With great patience, you can slowly unveil the real difficulties of music. The child will follow you if they have had fun. I've never found a kid who didn't respond to this approach.
Parents Need Patience
This method, entirely successful for the child, requires one thing from parent and teacher: patience. Many kids move beyond numbers in a few months, but other kids cling to it, usually the youngest kids. Don't forget that numbers allow any child to play music far harder than what they can read from musical notation. Thus six year olds are capable of playing the Moonlight Sonata in simplified form, and thousands of other pieces that will interest them far more than the "cardboard" music found in the standard beginner's texts.
Numbers also allow the teacher time to slowly work into reading music, instead of the "cold immersion" used today. Cold immersion does not work for anyone except a very tiny number of prodigies who may quit anyway. I realize this is the opposite of what you've been told, which is that only discipline will work, that reading music must be mastered first. But they are wrong, and the kids are the evidence. Allow kids room to grow at first. The reward comes later.