Hi there
If your class is not an examination-oriented one, then you could have some fun in giving them poems, tongue twisters and songs. However, this should only be done once your students are able to articulate phonemes quite well. Drilling them on minimal pairs is one of the activities that you could do in class. Voice projection and shaping the mouth correctly is equally important. This is because, unlike Japanese or Mandarin, the English language requires a lot of lip movements.
Good luck
Regards
Kev