on the back of the toilet door, havy at the a  page.. each time he goes toilet in the poty allow him to take a sticker and stick it on the page. it worked miracles for my nieces and nephews.  we also had a timer that went of about every half hour to remind them to check if they need the toilet. positivity and encouragement is the key. praise him for doing right but dont get angry if he has an acccident. He is after all only lreaning and life is busy at that age! good luck