Have your child help you with letters, even such routine ones as ordering items from an advertisment or writing to a business firm. This helps the child to see firsthand that writing is important to adults and truly useful. There are numerous games and puzzles that help a child to increase vocabulary and make the child more fluent in speaking and writing. Remember, building a vocabulary builds confidence. Try crossword puzzles, word games, anagrams and cryptograms designed especially for children.
Flash cards are good, too, and they're easy to make at home.
Suggest making lists. Most children like to make lists just as they like to count. Making lists is good practice and helps a child to become more organized. Boys and girls might make lists of their records, tapes, baseball cards, dolls, furniture in a room, etc. They could include items they want.