Focus on pronunciation issues that cause intelligibility problems.
Example: most people from other languages can’t pronounce TH, but in most cases, that doesn’t stop them from being understood.
Think about all the different aspects of pronunciation (consonant sounds, vowel sounds, syllable stress, word stress, thought groups, linking, cadence, prosody, etc), and how much “bang for the buck” is possible.
Example: incorrect syllable stress affects intelligibility quite a bit and is not that difficult for students to learn. The pronunciation of sounds that don’t exist in a student’s language may affect intelligibility (depending on the sound) and are really hard for students to learn & apply consistently.
Techniques for teaching pronunciation - learned from teaching a short English pronunciation class for Vietnamese & Thai speakers
Webinar recording: Pick your battles: best practices for helping students with pronunciation
Great, clear pronunciation videos: Elemental English
Teaching -ed pronunciation - a sample lesson, and materials
Eva Easton - great videos about specific pronunciation issues