Write one letter on each note card. On the same side, next to or below the letter, write the phonetic spelling, or sound, for that letter.
On the other side of the note card, write the letter only.
Read through the note cards, using the side with the letter and phonetic spelling of the letter on it rapidly. Repeat this process until some letters are recognizable without reading the phonetic spelling.
Flip the note cards over and use the side with only the letter written. Name, aloud, each letter on each note card. Put letter names that are known within three seconds into one pile and those that take longer or are unknown in another.
Review the sides with both the phonetic spelling and the letter for those cards in the "unknown" pile. Continue until they are more familiar.
Review all letters daily, using the side with the letter sounds as necessary. Do not allow errors more than once, without reverting back to the letter sound side of the cards. This limits the potential to learn the information incorrectly. Store index cards with a rubber band to avoid losing letter cards.