Handwriting Without Tears has an excellant preschool writing program. They use wooden letter shapes, roll a dough letters, magnetic letters to make learning fun! I would encourage you to use large surfaces such as chalkboards and dry erasable boards for practicing letters rather than work sheets. We have better motor memory which we need for remembering letters in our larger joints and muscles. When a child writes large and on a vertical surface, he can see his hand move, feel his arm move while listening to the instructions for making the letter. I would also encourage you to get the specific instructions for the letter and numbers from the school he attends so he won't be confused learning two different sets of letters/numbers. Most of all have fun with your child!