Teach the alphabet in the correct order using a book. Create your own book of letters or buy one. Have an image for your child to tie to each letter, such as an animal or cartoon mascot that will help them remember the letter.
Use the alphabet song to reinforce the order of the letters. Sing the song to your child several times then ask her to sing along. Sing through the song enough times and your child will be able to remember it.
Create flashcards to teach your child the sound that each letter makes. Start by showing him the letters and having him say which letter he is looking at then move on to showing him the letters and having him make the letter's sound.
Create new flashcards with pictures. Practice with your child to identify the object in the picture, say the word, and say the letter that it begins with. You can also do this outside of the lessons, for instance pointing to a tree and reminding her that it starts with a "T" sound.
Personalize the learning experience by using the child's name to teach the letters in it and the concept of grouping letters together to form a word. You can also teach him to write his name in order to tie in the mental side of learning with a physical experience.