Flashcards are good for memorization and reciting back. Take 3x5 index cards and write one word on one side of the card. To save paper, you can also write a second word on the other side of the card, just as long as you make sure to choose a marker or pen that will not bleed through. With your child, take the flash cards and have him recite each word. Flashcards are a great tool because they are portable and easy to use anywhere and anytime you have a few free minutes.
Being able to recognize the words that your child sees is a good indicator that she is starting to pick up the words and retain them in her memory. Test her knowledge by taking a newspaper or magazine and hand her a highlighter. Have her highlight all of the high frequency words that she sees. When she is done, go over them with her to verify that everything she highlighted is correct.
If you have access, take the books that are being read in your child's class into your home. Sit down with him and have him read the book with you and listen for proper annunciation of the words. By repeating the reading done in class at home, it will help him to retain the words he heard in class during the day.
To further engrave high frequency words and sounds into your child's memory, have her replicate the words she is seeing. You can take the flashcards that you made and have her write each letter in each word on a piece of paper. Even though this activity may seem too easy, the repetition of seeing the word, saying the word, and then herself writing the word will help her remember them in more than one way.