When it comes to the word “O” what you can do is that you can cut the letter “O” on a card paper (make sure that it’s big enough that it can fit your head), you then can wear the letter “O” on your head and play a game with your child like ‘hey! I am Mr. O”.
Now, as far as the sound of the letter “o” is concerned, well, you obviously need to use your vocals for that and if you want to learn the process to be even quicker then just simply head to Youtube and search for different lessons on the letter “O”. The visuals will attract your child so he will automatically listen to what’s being said in the video and well, these online teachers are professional people so they know how to attract a child and make him learn something.