Teach in small groups. Each child has to participate and be fully involved for success. If there are no assistants available, teach a small group while the rest of the class is busy with other activities. Of course, if you're teaching your child at home, this will not be a consideration.
Use pictures combined with the words. Humans tend to think visually and children are no exception. A related picture helps children retain the meaning of a word, mentally linking the word to the picture when they see the word again. Some words, such as "it" or "the," may not lend themselves to pictures, but most do. A bit of imagination can make even seemingly difficult words memorable. For instance, a monster named "It" my help with retention. Have children draw their own pictures to illustrate key sight words.
Read words aloud and have the children repeat them while pointing to the word written on a card. Children already know these words and use them every day, so the sight and sound combined can lock the sight word into their memory. Have children use the word in a sentence to provide context. Read silly sentences containing the sight words while showing the word to stimulate the children's imagination and give them more memories of what the word is when they see it again.
Use a story book to help kids recognize sight words. Read the story slowly and have each child in turn point out sight words as they occur. Most children greatly want to learn to read; they will be proud of being able to recognize words and will concentrate hard on each word as it is read. Many will try to jump ahead and spot other words on the page, but try to keep them focused on one sentence at a time.
Send a list of sight words home with each student and have parents stress those words when reading to their children at night. Kids will want to show off what they have learned when they get home, and repetition is key to internalizing the words so that teaching real reading in coming years will be easier.