An activity I did with my kids for the pronunciation of H was two parts. First, you must introduce how to make the H sound. I told them all to take a deep breath and make the huuuh sound. Then I did a dictation (student to student) with sentences like, "Hi, how are you?" "Happy hippopotamuses eat huge hamburgers." etc. Then I played a game where the class was divided into two teams, and played a game where one child was at the board from each team. Teammates had to yell out the word and the first one to write it correctly gained a point. The cards read hit/it, hat/at, ham/am, heel/eel, heat/eat, hill/ill, hi/I, etc. So the pronunciation was important.