Assess the child's knowledge of the alphabet. If a student does not know the names of all the letters of the alphabet, one cannot assume the child will know the sounds the letters make.
Practice making letter sounds. Start with the simple individual sounds each letter makes and, upon mastery, gradually move to more complex consonant and vowel combinations. Use a lot of variety in sound instruction; it can become boring very fast. Play games using letter magnets, flash cards or letter blocks. Look for and cut out letters and letter combinations from the newspaper.
Combine letters and letter combinations to create words. Start with simple sight words and, upon mastery, gradually increase the difficulty of the words. Apply the same decoding strategies you used with sounding out letters to prompt the child in sounding out new words. Say things like, "What sound does 'c' make? What sound does 'a' make? What sound does 't' make? Now put the three sounds together." Again, vary the instructional techniques you use to increase learning and motivation.
Teach the rules of the English language. After the child has mastered simple letter combinations, begin teaching combinations that sound alike but are spelled different, like 'ea' and 'ee'. Teach suffixes and prefixes and the rules that apply to them. Gradually add skills as the child masters each lesson.
Review frequently. Even if a child has mastered a language skill, repetition is essential if the child is to retain the information and be able to apply it in the classroom and in everyday life.
Read books that have mastery words in them. Obtain a recommended reading list online or through your child's school. Inquire at your library which books would be appropriate for your child's level. And read, read, read! Practice every day.