Use alphabet flashcards to teach your class the primary sound of each letter of the alphabet. Most consonants make only one sound, but for the ones that make two, choose to teach children only the most often used sound in this stage. Similarly, for vowels choose the short sounds first.
Sing songs and play games that reinforce the letters and their sounds. Have children manipulate magnetic letters, draw them with crayons, shape them from play clay, and sing them in order. Get all the senses involved as you reinforce this fundamental building block.
Similarly, the initial memorization of numbers is easy for children to grasp. Use simple flashcards to teach them initially, but it's practical application that will turn those memorized names into mathematical concepts. Count everything, from sugar cubes to the shoes of every child in the class. Make counting from one to 20 so common in your classroom that children come to expect it.
Count to three before you open a door. Count to five before you allow the children to leave for recess or transition to a new activity. Count the number of children in line before you leave, and count the number of hands raised when you ask a question. Simple everyday usage like this allows a child to grasp the complexities of math without the pressure of pen and paper assignments.
Reinforce your efforts with visual aids in your classroom. Make sure you have both the numbers and letters displayed prominently in your classroom. Ask a child to tell you the sound another child's first name starts with and have him count the number of letters in the name.
Sing songs about letters and numbers, including the alphabet song and "10 Little Monkeys." Label everything in your room, especially if its name is a short word. In this way, not only will you be reinforcing letters and sounds, you'll be aiding them in future studies by giving them sight words to memorize.
Parental involvement is very important to your teaching aims, especially in preschool. Send home suggested activities on a regular basis. Give the children simple homework. For instance, if you are attempting to reinforce the letter E, have the child count the number of eggs in his refrigerator and write it on the paper you've provided him. Have him trace a letter E and provide a place for parents to sign the paper before bringing it back.
Schedule regular meetings with parents to discuss a child's progress. Tell parents if she if falling behind, and if so, be prepared with reinforcement activities that the parents can use to help her along.