Respect the child's native language. Teaching a child a language requires cooperation and team work. To build this cooperation, you'll need to develop a good rapport with the child. The best way to ensure this is to respect the child's native language and speak to the child in that language if possible. It's important for children to understand that English is not intended to replace their native language, but simply make them able to communicate with others.
Read picture books to the child. Just as with native speakers, a wonderful way to help a child build vocabulary is to read aloud to him. As you read the books, let the learner look at the pictures. A non-native speaker will pick up new words or phrases by listening to the words and looking at the pictures simultaneously.
Pair the child with an English-speaking buddy. As the two children engage in play, the native speaker's English usage will rub off on the learner.
Focus on key words. Don't overwhelm the child by presenting him with too many words at once. Instead, focus on key words that have particular relevance to the student. By teaching him school-related words like teacher, principal, and lesson, you can prepare the student for his entrance into an environment of formal learning. After the student masters one set of key words, present him with another so that his vocabulary continues to grow.
Build a word wall. Write new words that the child learns on sentence strips, and place these words on the wall. Let the child draw a picture to go with each word so that she has a visual reminder of the term, and place this picture next to the word-bearing sentence strip. This keeps the words fresh in the child's mind and gives her a reference point if she forgets a word that she had learned.
Take the child into the community, and encourage him to use his English skills. When visiting a store or ice cream parlor with the child, let him do the talking. It might take him longer to communicate his needs in English, but this opportunity will enhance his overall understanding of the English language and help him communicate effectively using his new language skills.