Show each color of the rainbow. You can use things such as markers or pieces of construction paper to demonstrate the colors.
Put the colors in order. A rainbow always has the same color order: red, orange, yellow, green, blue, indigo and violet.
Say the name of each color out loud while writing it in a vertical line on a board. This will create the letters R-O-Y-G-B-I-V at the beginning of the vertical line.
Explain that these letters can be remembered by remembering the phonetic pronunciation for R-O-Y-G-B-I-V as Roy G. Biv.
Add activities to your lesson. Allow the children you are teaching to draw their own rainbow with colored markers, for example, or let them construct a rainbow out of colored paper.