People put piano letters on the keys as an aid to reading music. Use masking tape, Scotch Tape or Post-It notes. Letters on the keys provides security. For younger kids, letters on the keys helps them learn the names of the notes. As with numbers, letters are a means of delaying reading music. The reason for this is that learning to read music is a long process that often frustrates kids.
The Teacher's Job
To make this method work, the parent or teacher must put the letter names of the notes directly over the notes on the page. This means the child is not really reading music but reading the letters.
Finding the Notes
Five lines on page, keyboard below
Kids are very confused by the relationship of the "staff" (above) and the keyboard (below.) Then best method is to give kids visual reference points on the keys, as in the drawing below. The red sticker is on "Middle C."
The Next Steps
After this, you need to help the child correspond the notes on the page to the keys on the piano, as in the drawing below.
The first realization you will have is that learning the names of the notes has little to do with navigating the piano keyboard. A far better strategy is to teach the child the physical layout of both the notes on the page, and their corresponding locations on the keyboard. See the drawing above.
Putting letters on the keys will help the child learn the names of the notes. The problem is that it will not help them navigate the relationship between the staff and the keys. Piano letters are still a valid means of starting a child at the piano. Anything that delays reading music until their brains are ready is good for the child.