Review sounds daily. Display vowel sound flash cards which you can make yourself with index cards or construction paper. Your school's phonics program may include premade flashcards in the teacher's kit.
Keep a chart of all vowel sounds in full view of the class. Many teacher supply or dollar stores have charts you can purchase. The most effective way, however, is to write the chart yourself. As children master vowel sounds, write them on the chart until you have covered all required sounds or blends.
Utilize computer-based games if you have a computer lab at your school or at least one computer in your classroom. Internet4Classrooms,com is just one of many online sites with vowel-sounds games that are easy for second-graders to navigate. Children click on pictures that contain the displayed vowel or look at three words and choose the one spelled correctly with either a long or short vowel.
Get kids to listen to vowel sounds. This is important because some children may know that "ay" says the sound for "a" as in play, but need to hear other people pronounce it. For example, record yourself or an advanced reader in the class say vowel sounds. Then have struggling students listen to these recordings and repeat them aloud.