What do you find difficult about English pronunciation? (as a learner or as a teacher teaching pronunciation).
Pronunciation consists of a considerable amount of complex features:
the phonemic system which entails the full understanding of:
vowels (single: short vs long/diphthongs)
Other features such as:
Word stress, Sentence stress, connected speech, intonation
Coming to grip with all these components is a real learning and teaching challenge
What can we do to improve our learners’ pronunciation?
It might be sensible to first let learners notice all these aspects and then gradually engage them in communicative pronunciation tasks.